BELIEVE IN ALGEBRA, NOT CALCULATOR

  Рет қаралды 1,189,552

blackpenredpen

blackpenredpen

5 жыл бұрын

Sign up for an free account at brilliant.org/blackpenredpen/ and try their daily problems now. You can also get a 20% off discount for their annual premium subscription so you can get access to ALL of their awesome designed courses!
For more resource, please visit: www.blackpenredpen.com/calc2
Click to subscribe for more math contents: kzbin.info...
Check out my T-shirts & Hoodies: teespring.com/stores/blackpen...
support bprp on Patreon (there's a discount code to bprp Teespring store for everyone) / blackpenredpen
I create my site www.blackpenred.com on Wix, give it a try: wixstats.com/?a=25754&c=124&s1=
Check out my site & social media
😃 blackpenredpen.com
😃 / blackpenredpen
😃 / blackpenredpen
Thank you for your support!
blackpenredpen | 曹老師

Пікірлер: 1 700
@aasyjepale5210
@aasyjepale5210 5 жыл бұрын
i did some mental math, but hit a wall at trying to find the square root of 63,252,753,001
@iamgroot3615
@iamgroot3615 5 жыл бұрын
that’s some impressive mental math assuming you’re telling the truth . Is there a trick or something
@AngryAxew
@AngryAxew 5 жыл бұрын
@@iamgroot3615 theres no trick hes probably lying
@AngryAxew
@AngryAxew 5 жыл бұрын
r/iamverysmart
@marvinfung2050
@marvinfung2050 5 жыл бұрын
AngryAxew there's no reason not to be able to mental math those numbers Like 500(500+1) which is easier which is 250000+500 and it similar to the end
@narayanankannan6787
@narayanankannan6787 5 жыл бұрын
I mean it's OBVIOUSLY 251501.
@Armbrust666
@Armbrust666 5 жыл бұрын
Wow... this essentially proved that if you take the product of four consecutive -numbers- integers and add one to it, than it's gone be a square number.
@ClimateAdam
@ClimateAdam 5 жыл бұрын
Awesome! Good spot!
@fanyfan7466
@fanyfan7466 5 жыл бұрын
Gábor Tóth holy shit you’re right! That’s crazy man
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Yup!!
@kingbeauregard
@kingbeauregard 5 жыл бұрын
The most pathological case I can think of is -1 thru 2, and yes indeed I get 1, which is a perfect square.
@pcklop
@pcklop 5 жыл бұрын
My professor had us prove a more general result: take the product of four numbers in arithmetic sequence, then add the fourth power of their common difference. Show that the result is a perfect square.
@threadeater345
@threadeater345 5 жыл бұрын
1990: we'll have flying cars by 2019 2019: 2=1+1, wow I'm a genius
@blackpenredpen
@blackpenredpen 5 жыл бұрын
LOL
@ghotifish1838
@ghotifish1838 3 жыл бұрын
2+2 is 4, minus one that's three quick maths
@Kyanzes
@Kyanzes 3 жыл бұрын
Flying cars... you can't even have a sharpie that could change color. Say, red and black.
@santinodemaria2818
@santinodemaria2818 3 жыл бұрын
@@ghotifish1838 topical meme reference
@unutentediyoutube3282
@unutentediyoutube3282 3 жыл бұрын
Well it can also be 2=500-498
@yuliaokhremenko6613
@yuliaokhremenko6613 5 жыл бұрын
I just started learning English, but the explanations are clear and interesting even at my levels of English. Thanks a lot 😁👍
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Юлия Охременко I am Glad to hear!
@enhace15anos.83
@enhace15anos.83 4 жыл бұрын
x2
@corona8073
@corona8073 4 жыл бұрын
U r indian Chinese korean or ....???
@donovanholm
@donovanholm 4 жыл бұрын
@@harelavv8806 the name may seem obviously Russian to some but not all
@siddharthsoni2101
@siddharthsoni2101 3 жыл бұрын
@@blackpenredpen hii
@Hypoli
@Hypoli 3 жыл бұрын
My last words whispered in a final breath : "Don't forget the +1"
@not_So_Random-Dude
@not_So_Random-Dude 3 жыл бұрын
😂
@68plus1.
@68plus1. 2 жыл бұрын
LMFAOOO
@naiknaik8812
@naiknaik8812 2 жыл бұрын
He never resumed the video
@user-tk4dj4il5s
@user-tk4dj4il5s 11 күн бұрын
He added the one wdym 🧐
@sethdon1100
@sethdon1100 5 жыл бұрын
Olympic math taught me that insanely hard problems often had elegant solutions, this is no exception.
@blackpenredpen
@blackpenredpen 5 жыл бұрын
: ))))
@hafizh8461
@hafizh8461 4 жыл бұрын
@@leif1075???
@hemandy94
@hemandy94 4 жыл бұрын
@@leif1075 people like these are called problem solvers...
@drudi1
@drudi1 4 жыл бұрын
@@leif1075 well it took me about 5min to solve it so I think is not impossible to solve. All of this types of equations where you have 4 consecutive numbers multipled are done like this
@jayasri6764
@jayasri6764 4 жыл бұрын
Lol,This problem is actually super easy,(Every single Olympiad contestant would have solved this question,at some point of their life) .Insanely hard problems need not have simple solutions . That's a downside of the math Olympiad .They make you expect difficult problems have simple solutions.(Although,most imo contestants don t fall for this fallacy).Real insanely hard problems have not been solved by anyone,yet.
@BryanLu0
@BryanLu0 5 жыл бұрын
Instead distributing at 4:18 u = x^2 + 3x + 1 (u - 1)(u + 1) + 1 = u^2 So the root is x^2 + 3x + 1 = 251501
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Bryan Lu omg that cat!!!!
@AmitBentabou
@AmitBentabou 5 жыл бұрын
Or even u=x^2+3x, then u^2+2u+1
@matias12381
@matias12381 5 жыл бұрын
digno de nyan cat, jajajajaj
@mattat3847
@mattat3847 5 жыл бұрын
My life is a lie. I thought u subbing was only for integrals
@RunstarHomer
@RunstarHomer 5 жыл бұрын
@@mattat3847 nah man, sub whenever it makes the problem simpler
@leagueplays2100
@leagueplays2100 5 жыл бұрын
i put it in my calculator and got 251501, that was easy
@bowtangey6830
@bowtangey6830 4 жыл бұрын
Boo!
@Netherexio
@Netherexio 3 жыл бұрын
@The Balton American calculators are beasts
@paradox9265
@paradox9265 3 жыл бұрын
@@Netherexio Agreed but Americans aren’t
@Netherexio
@Netherexio 3 жыл бұрын
@@paradox9265 What do you mean?
@user-yp6eb5wj4w
@user-yp6eb5wj4w 3 жыл бұрын
It was easy, but not so beautiful like this)
@ganaraminukshuk0
@ganaraminukshuk0 5 жыл бұрын
"If you're using a calculator, why are you watching this video?" Sanity check.
@blackpenredpen
@blackpenredpen 5 жыл бұрын
hahahahaa
@andrel8243
@andrel8243 3 жыл бұрын
I am a calculator, not a person
@mysticdragonex815
@mysticdragonex815 2 жыл бұрын
*laughs in Shakuntala Devi
@TheS1lentX
@TheS1lentX 5 жыл бұрын
Jeez thats smart *proceeds to use the calculator to prove that 251501 is the right answer*
@blackflash9935
@blackflash9935 5 жыл бұрын
5:48 “Back in my day kids would use *ALGEBRA* but now their brains are rotting from these darn *CALCULATORS* ”
@mr.n1933
@mr.n1933 5 жыл бұрын
Dafuq did i jusf watch.i lost it when the 2=1+1
@executorarktanis2323
@executorarktanis2323 4 жыл бұрын
You are not nerdy enough
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Did you know that 2 = 1 + 1?? I bet not! jk : )
@williamadams137
@williamadams137 5 жыл бұрын
blackpenredpen No i don’t, i need a calculator to this
@snejpu2508
@snejpu2508 5 жыл бұрын
That's pretty funnt, but sometimes such things are the most difficult to see, for example: we have f(x)=x^4+8x^3+18x^2+8x+17, and a question, for which x, the function f(x) is a prime. You can check infinitely many cases and never know the answer, but what makes this question easy (but on the other hand is not so obvious), is that 18=17+1. Because then we have (x^2+1)(x^2+8x+17), which has to be a prime. One of them has to be = 1, the other one has to be some prime then... We are left with only 2 cases, because we know, that 18=17+1. : )
@theolbiterator5408
@theolbiterator5408 5 жыл бұрын
No but I knew 2= 0.9+1.1.
@chaitanyagadekar5025
@chaitanyagadekar5025 5 жыл бұрын
I Known 2+2 = 5
@clubstepdj
@clubstepdj 5 жыл бұрын
What i know is 5/2 = 2 with int data type
@maheshagrawal7779
@maheshagrawal7779 5 жыл бұрын
no 2=1+1/2+1/4+1/8+1/16... you have got many misconceptions blackpenredpen!!!
@iabervon
@iabervon 5 жыл бұрын
When he writes 1, he's obviously just abbreviating 1/2+1/4+1/8+1/16+...
@InDstructR
@InDstructR 5 жыл бұрын
@@iabervon and when he writes 1/2 he's abbreviating for 1/4+1/8+1/16+...
@agces2001
@agces2001 5 жыл бұрын
@@InDstructR And when he writes 1/4 he's abbreviating 1/8 + 1/16 + 1/32+...
@InDstructR
@InDstructR 5 жыл бұрын
@ki kus won't stop me, And when he writes 1/8 he's abbreviating 1/16+1/32+1/64+1/128+...
@shounakghosh8595
@shounakghosh8595 5 жыл бұрын
Whoa that converged quickly
@tanmay8017
@tanmay8017 2 жыл бұрын
I remember solving this exact question in my JEE ( Mains ) exam.
@classicmelodyvetrivel710
@classicmelodyvetrivel710 2 жыл бұрын
@Sanat R mains usually has easy questions
@Avighna
@Avighna Жыл бұрын
@Sanat R - Study Vlogs Sure, yeah, "easy question" 😬
@Avighna
@Avighna Жыл бұрын
@Sanat R - Study Vlogs Woah, really? What kinda questions do they ask? Could you send me a link?
@dr3w199
@dr3w199 5 жыл бұрын
Nice. I did it this way: Assume that the expression is a square number so: x(x+1)(x+2)(x+3)+1 = n^2 x(x+1)(x+2)(x+3) = n^2 - 1 x(x+1)(x+2)(x+3) = (n+1)(n-1) What I did then is realise that the factors of the product on the right differ by 2. Playing around you can find that: x(x+3) = x^2+3x = n-1 (x+1)(x+2)=x^2+3x+2 = n+1 So n = x^2 + 3x + 1 Not as neat as your method though! Thanks for the video
@juanbomfim22
@juanbomfim22 5 жыл бұрын
OMG ive almost done it completely. i just stopped at (n+1)(n-1) lol WD! i mean 'not that almost' lmao
@joshuamason2227
@joshuamason2227 5 жыл бұрын
How do I play around with it
@dr3w199
@dr3w199 5 жыл бұрын
@@joshuamason2227 Well you have the product of 3 binomials and a monomial for which we can multiply in any order. If you try a few cases, or think about it you spot that x(x+3) and (x+1)(x+2) have a difference of 2.
@joshuamason2227
@joshuamason2227 5 жыл бұрын
@@dr3w199 okie
@sunnykarwani3556
@sunnykarwani3556 3 жыл бұрын
Damn... It's a great method. Neat work. 💯
@steve2817
@steve2817 5 жыл бұрын
1 + 1 = 3 And sinx/n=six=6.
@rio_agustian_
@rio_agustian_ 5 жыл бұрын
You stupid, 1 + 1 ≠ 3 3 = 2 + 1 π = 2 + 1 π - 1 = 2
@CookieJar2025
@CookieJar2025 5 жыл бұрын
@@rio_agustian_ so π = 3 lol nice discovery
@Kevin-14
@Kevin-14 5 жыл бұрын
@@CookieJar2025 e = 3 = π
@SameerKhan-nd5qb
@SameerKhan-nd5qb 5 жыл бұрын
@@rio_agustian_ noob
@SameerKhan-nd5qb
@SameerKhan-nd5qb 5 жыл бұрын
@@Kevin-14 lool nooob
@rd8396
@rd8396 5 жыл бұрын
Take x ^2 + 3x = a Then in step 2 a(a+2) + 1 a^2 + 2a + 1 = (a+1)^2
@mat1305h
@mat1305h 5 жыл бұрын
Yes much easier, and you see it imediatly too.
@Polarspy
@Polarspy 5 жыл бұрын
was about to say this, i think it's a lot more intuitive
@milanmitreski7657
@milanmitreski7657 5 жыл бұрын
Isn't it beautiful how one problem can be solved in diffrent ways, even if the idea and the method are nearly the same. That's why we love maths.
@sanjaisrao484
@sanjaisrao484 5 жыл бұрын
@@milanmitreski7657 Yes
@akshetpatial5466
@akshetpatial5466 5 жыл бұрын
You extra smart boy the time required here will be same
@pfever
@pfever 5 жыл бұрын
Sorry...Time over! give me your exam!
@TheGaberGuy
@TheGaberGuy 3 жыл бұрын
Blew my mind! Earned yourself a new subscriber! Keep up the good work!👍
@Inujasa88
@Inujasa88 5 жыл бұрын
0:10 is this a pewdiepie reference? 😂😂
@albel2094
@albel2094 5 жыл бұрын
He liked it!!!
@randomdude9135
@randomdude9135 4 жыл бұрын
@@albel2094 yupp
@randomdude9135
@randomdude9135 4 жыл бұрын
Yupp
@jekoddragon6227
@jekoddragon6227 5 жыл бұрын
now do it with CALCULUS
@davidappell3105
@davidappell3105 3 жыл бұрын
Why do you think this is funny?
@gabrielpinhal8325
@gabrielpinhal8325 3 жыл бұрын
@@davidappell3105 because suffering is funny
@sanchit6107
@sanchit6107 2 жыл бұрын
@@davidappell3105 Its FUNI
@agabe_8989
@agabe_8989 4 жыл бұрын
0:01 that's my life philosophy now
@DatSwif
@DatSwif 3 жыл бұрын
This is beautiful. I've been looking at it for five hours now
@chaitanyagadekar5025
@chaitanyagadekar5025 5 жыл бұрын
0:09 That was PowerFul
@lucasxue2211
@lucasxue2211 2 жыл бұрын
i remember my math teacher asking me to prove that n(n+1)(n+2)(n+3) + 1 is always a perfect square given that n is an integer
@ericzgrey
@ericzgrey 3 жыл бұрын
I love this. You did a great job of laying out a good challenge.
@tiborgrun6963
@tiborgrun6963 5 жыл бұрын
Not only 2 = 1+1, but also 0 = 1-1. From the second row: (x^2+3x+1-1)(x^2+3x+1+1)+1 and per the third binomial equation = (x^2+3x+1)^2 -1^2 +1 = (x^2+3x+1)^2
@etemkaandelibas3649
@etemkaandelibas3649 5 жыл бұрын
I didn't understand. Where did you use binomial expansion
@jinja3113
@jinja3113 5 жыл бұрын
0 = 1-1 1 = 1*1 2= 1+1
@yogeshpathak73
@yogeshpathak73 4 жыл бұрын
I didn't see any binomial here... But what i see is that you used the form (a+1)(a-1) + 1 = a^2 - 1 +1= a^2
@Bayerwaldler
@Bayerwaldler 4 жыл бұрын
@@yogeshpathak73 I think Tibor Grün is from Germany. In German school curriculum the formula (a+b)*(a-b) = a^2 - b^2 is known as 3. binomial formula. b=1 is a special case.
@yogeshpathak73
@yogeshpathak73 4 жыл бұрын
Oh ok... Didn't know that. Thanks.
@mhm6421
@mhm6421 Жыл бұрын
Continueing from: sqrt( (x^2 + 3x) (x^2 + 3x + 2) + 1 ) let y = x^2 + 3x sqrt( y * (y + 1) + 1 ) = sqrt( y^2 + y + 1 ) = sqrt( (y+1)^2 ) = y + 1 = x^2 + 3x + 1 = (x + 1) (x + 2) - 1 = 501 * 502 - 1 = 251501 much easier to multiply :p
@razvy3827
@razvy3827 Жыл бұрын
that is what i wanted ti type nice 👍
@asa-ze1kn
@asa-ze1kn 5 жыл бұрын
I'm only in 8th grade Algebra 1 but I was using variables to find how some of your factorizations works. You went from (x^2+3x)(x^2+3x+2)+1 to (x^2+3x)(x^2+3x+1)+(x^2+3x+1). What I did was set (x^2+3x) to a variable (a). (a)(a+2)+1 a^2+2a+1 (a+1)(a+1) Now substitute back in. (x^2+3x+1)(x^2+3x+1) When in doubt use variables..
@trueriver1950
@trueriver1950 4 жыл бұрын
Yes, that's using even more algebra than BPRP did.
@zocker2586
@zocker2586 4 жыл бұрын
Well yes because using the variables is actually the logic behind the solution, it's just that it was invisible throughout the process :D
@baranibarani4970
@baranibarani4970 4 жыл бұрын
Where r u from?
@sanjanabiswas9774
@sanjanabiswas9774 3 жыл бұрын
Agreed! Variables always help to proceed the solution.
@enricomassignani
@enricomassignani 3 жыл бұрын
I put x=500 but multiplied everything. In the end i got to sqrt((x+y)^2) with x=500 and y=501^2
@ugursoydan8187
@ugursoydan8187 3 жыл бұрын
a very good perspective and a very good solution. thank you!!!
@SawkTheFighter13
@SawkTheFighter13 2 жыл бұрын
Why are your videos so entertaining? I'm so glad I came across this channel.
@isaacdeutsch2538
@isaacdeutsch2538 4 жыл бұрын
I chose to make x = 502, which ends up yielding a nice difference of squares and a two term quadratic, which is much easier to distribute. The quartic you get has a palindromic pattern reminiscent of pure binomial coefficients, making it tempting to say the golden ratio is a root. It is, in fact, a root, so synthetically divide the quartic by the golden ratio identifying polynomial, x² - x - 1. You end up with the golden ratio identifying polynomial again, meaning that the original quartic in that square root is (x² - x - 1)², so cancel the power and the root. Plug 502 back in for x, some quick multiplying and subtracting by hand and you've got 251501.
@msmmath87
@msmmath87 5 жыл бұрын
Really good solution! GOOD Teacher👍
@mathstraining6996
@mathstraining6996 5 жыл бұрын
Really good video. Thanks for inspiring students. Keep it up
5 жыл бұрын
This was fantastic. I wish to thank you for your videos.
@MrShad
@MrShad 5 жыл бұрын
What a incredible content. Im a student of math (i'll be a teacher in the future) from Brazil. Thank you so much for sharing knowledge!
@detachedmars158
@detachedmars158 5 жыл бұрын
You can also put a +1-1 inside the x^2+3x bracket and it'll be in the form of (a+b)(a-b).
@kilindogma9711
@kilindogma9711 5 жыл бұрын
that's what i thought he was gonna do as well but what he did was cool as well.
@ssdd9911
@ssdd9911 5 жыл бұрын
why?
@iabervon
@iabervon 5 жыл бұрын
Yeah, (x-1)(x+1)+1=x^2-1^2+1 seems easier to find than multiplying out exactly the right portion of the big expression.
@-Mohammed_S
@-Mohammed_S 3 жыл бұрын
Your explanation is awesome . I like your teaching very much. Thanks
@makotoca4429
@makotoca4429 5 жыл бұрын
This just blowed my mind!!! Love this
@workout9594
@workout9594 4 жыл бұрын
3:20 I solved it differently. Let y= x^2+3x. Then substitute y into the expression making y(y+2)+1, distribute so y^2+2y+1 and that is a perfect square of (y+1)^2. Here, the square root and exponent cancel each other leaving y+1, sub back in x and then easily find the answer :)
@matthewmanzanares6798
@matthewmanzanares6798 Жыл бұрын
this is also what I did and I think that this is a bit better because you don't have to split 2 into 1 + 1 and do the rest
@cheesecircle3033
@cheesecircle3033 8 ай бұрын
That's what I did as well
@eannacoleman957
@eannacoleman957 2 жыл бұрын
I love the explanation, though I did it a bit differently. When I got to the second line, I substituted (x²+3x) as y and found that that worked much simpler than distributing 2 as 1+1.
@apanapane
@apanapane 5 жыл бұрын
That was beautiful. Thank you.
@zoroarklover363
@zoroarklover363 5 жыл бұрын
I love you, you make me remember stuff I had forgotten!
@almightyhydra
@almightyhydra 5 жыл бұрын
3:20 just put y = x^2 + 3x, then you have y(y+2) + 1 = y^2 + 2y + 1 = (y+1)^2. So the answer is y + 1, or x^2 + 3x + 1.
@cypherx7247
@cypherx7247 5 жыл бұрын
I also did it in this way...but that way was also fine...its all about which method comes in your head first
@lasergamer2869
@lasergamer2869 3 жыл бұрын
Dang that’s genius
@LudwigvanBeethoven2
@LudwigvanBeethoven2 5 жыл бұрын
Every body knows 1+1=2 but i know 1+1 =/= 3
@blackpenredpen
@blackpenredpen 5 жыл бұрын
♫♪Ludwig van Beethoven♪♫ Hahahhaha
@jgsh8062
@jgsh8062 3 жыл бұрын
I’ve got you all beat with 1+1 > 0
@JDguy11222
@JDguy11222 3 жыл бұрын
@@jgsh8062 nah mine's better 1+1≠1+1
@bucinoulje7505
@bucinoulje7505 3 жыл бұрын
i watched this video this video right before my math competition and the same type of question came up on the task sheet. Thank you very much!
@bucinoulje7505
@bucinoulje7505 3 жыл бұрын
for those wondering the question was 202120212019(202120212021)(202120212023) all over 100010001 x (202120212021 squared +4)
@thatssokwekwe
@thatssokwekwe Жыл бұрын
I expressed it as sqrt((501.5-1.5)(501.5-0.5)(501.5+0.5)(501.5+1.5)+1) You get two a^2-b^2 expressions that you can multiply out, add the 1, and then factor into a squared quadratic expression Very neat and, as someone mentioned elsewhere, it generalizes to “1 plus the product of any four consecutive integers is a perfect square”
@snatchngrab8262
@snatchngrab8262 3 жыл бұрын
The world needs more teachers like you. I'm more impressed by your teaching skills than any math. Much respect.
@paawanjethva
@paawanjethva 5 жыл бұрын
Everybody knows e^{iτ}=1 . . . . But I know 1=e^{iτ}
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Nice!!!
@paawanjethva
@paawanjethva 5 жыл бұрын
@@user-bd9mu3ee1i That's e^{iπ}. τ=2π
@fgvcosmic6752
@fgvcosmic6752 5 жыл бұрын
My mans using tau! Up top!
@peterg644
@peterg644 4 жыл бұрын
@@user-bd9mu3ee1i he's using tau not pi
@naysay02
@naysay02 Жыл бұрын
man this was amazing to watch! so clever!
@arkabhattacharya1792
@arkabhattacharya1792 2 жыл бұрын
The entry was epic and the whole video is interesting.
@DavidS-qn3jm
@DavidS-qn3jm 5 жыл бұрын
I did assume there was a nice solution, but expanding under the root to get x^4 + 6x^3 + 11x^2 + 6x + 1 was pretty easy, and then matching coefficients in (x^2 + ax + 1)^2 was straightforward too. But yeah, the main thing is to replace 500 by x. I don't think I could intuitively see which two of the brackets would make it easier, and I'm not sure that's a better method than expanding the whole thing to only 4 terms (plus the one on the outside).
@sadeekmuhammadryan4894
@sadeekmuhammadryan4894 2 жыл бұрын
There are things to learn from each of your videos 😁❤️
@deadvirgin428
@deadvirgin428 5 ай бұрын
Well yes, that's the point.
@neetabhojwani9924
@neetabhojwani9924 5 жыл бұрын
Nice video . I learnt a lot
@star_ms
@star_ms 2 жыл бұрын
Seemingly elementary problems can have wonderfully elegant solutions! All we need is to substitute a number with x, and the magic begins.
@martinepstein9826
@martinepstein9826 2 жыл бұрын
Nice factoring method but it might have taken me a while to spot. Multiplying out and factoring isn't so bad (x - 1)x(x + 1)(x + 2) + 1 = (x^2 - 1)(x^2 + 2x) + 1 = x^4 + 2x^3 - x^2 - 2x + 1 = (x^2 + bx +- 1)^2 = x^4 + 2bx^3 + (b^2 +- 2)x^2 +- 2bx + 1 We see this works if b = 1 and c = -1 so the answer is 501^2 + 501 - 1 = 500^2 + 2*500 + 1 + 500 = 251501
@jdsingh3607
@jdsingh3607 5 жыл бұрын
Now this video makes me like algebra
@FermionClasses
@FermionClasses 3 жыл бұрын
kzbin.info/www/bejne/jomVdXxvepatjJo
@kodichandrashekher7213
@kodichandrashekher7213 4 жыл бұрын
It is so interesting and good to remember. Thanks.
@balumathtech2022
@balumathtech2022 3 жыл бұрын
Nice... Great method of solving
@aikenkazim5318
@aikenkazim5318 5 жыл бұрын
please give an example differentiation of complex functions
@ozonejgs2887
@ozonejgs2887 5 жыл бұрын
I am so impressed with myself, I actually used the same method you did before watching the video =D
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Jan Wrobel nice!!!!
@kartikeyasingh8592
@kartikeyasingh8592 3 жыл бұрын
You are an absolute genius bro🤟🤟 I was surprised by your last step result 😱😱😱
@bernardelmargi9733
@bernardelmargi9733 3 жыл бұрын
This is very useful, I’m trying to think more outside the the box for hard mathematical equations either for proofs or something like this, I didn’t thing to make 500 = x, but it simplified it so much. This is a useful skill and I will be sure to use it
@imadkhan1825
@imadkhan1825 5 жыл бұрын
You can also this as x^2+3x=t and expression would become t(t+2)+1 =(t+1)^2 this que came in practice test for jee last week And guess what i solved that 😎😎😎👍👍
@laudine878
@laudine878 5 жыл бұрын
Doing a PhD in Literary Studies, but stuff like this is why I absolutely love maths ♥
@UberPretzel101996
@UberPretzel101996 5 жыл бұрын
Man, you deserve more subs!
@smragibrezwan2778
@smragibrezwan2778 5 жыл бұрын
WOW! Now that's an amazing way to solve it!
@whyit487
@whyit487 5 жыл бұрын
I love your videos about not using calculators (Like the Wolfram-Alpha video)! They're the best! Keep up the good work! It's nice going back to algebra sometimes...
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Why It? Yea me too. I try to mix things up a bit.
@mango417
@mango417 4 жыл бұрын
"And now, here's the deal"… You know that when he pronounces that phrase things are 'bout to get complicated.
@varunkashyap6571
@varunkashyap6571 5 жыл бұрын
Awesome solution to the question
@lisamariefan
@lisamariefan 3 жыл бұрын
Actually trying it out was fun, and there was some surprisingly elegant generalization going on behind the scenes.
@Mothuzad
@Mothuzad 3 жыл бұрын
Shout-out to my colorblind fam who can never tell when he switches pens
@ammardaffa
@ammardaffa 5 жыл бұрын
I know this kind of the prob, i use (n+1)(n+2)-1
@yannisdekonoha
@yannisdekonoha 2 жыл бұрын
When he drops the "Check this out", you know crazy stuff will happen on the board
@AdityaTiwari-wf2gi
@AdityaTiwari-wf2gi 5 жыл бұрын
Brilliant solution .keep it up
@moosemoosington1441
@moosemoosington1441 2 жыл бұрын
Dude, I always had a good grasp on algebra as a kid and in highschool I always aced most algebra, but somehow my teachers (and I) missed this property of algebraic equations. So freaking cool. It has been nigh on 15 years since high school, but I am still learning new and cool algebra. Thanks so much blackpenredpen!
@ishmeetsingh1146
@ishmeetsingh1146 5 жыл бұрын
Wow your method and my method are similar .....I had take the whole expression as y and then square it and then assume x to be 500 and multiplied and had taken x^2+3x to be z and at end I got y=z+1 that is y = x^2 + 3x + 1 and it's done
@ciahartsrodrigues8823
@ciahartsrodrigues8823 2 жыл бұрын
3:19 The "WOW". LOL
@ShaunakDesaiPiano
@ShaunakDesaiPiano 11 ай бұрын
3:32 perhaps an easier method to spot is if you partially expand the brackets so that you end up with (x²+3x)² + 2(x²+3x) + 1, which is precisely (x²+3x+1)²
@kinyutaka
@kinyutaka 5 жыл бұрын
I'm doing this on the toilet, so I only hope I'm starting correctly, with (500)(502)=(501²-1) and (501)(503)=(502²-1) But then again, we could cheat and go with (501)(502)=(501½²-¼) and (500)(503)=(501½²-9/4)?
@-a5624
@-a5624 5 жыл бұрын
I know this is not related to this video but I wanted to post this on a new video so you might see it :) your trick for integrals of thinking "wouldn't it be nice if..." has helped me so so much, so thank you :) love your videos!
@blackpenredpen
@blackpenredpen 5 жыл бұрын
Awww thank you!!!!!
@Rishith198
@Rishith198 Ай бұрын
wow, just wow!! Fascinating !!
@PedroMartins-ux7mv
@PedroMartins-ux7mv 3 жыл бұрын
Very elegant solution
@noverdy
@noverdy 5 жыл бұрын
Everybody know e^2.pi.i = 1 . . But I know 1 = e^2.pi.i
@mundane3809
@mundane3809 5 жыл бұрын
Wrong it's - (e ^ pi × i)
@nikolas9105
@nikolas9105 5 жыл бұрын
@@mundane3809 Nice try but thats -1 ignoring your name
@mundane3809
@mundane3809 5 жыл бұрын
@@nikolas9105 no e ^ ( pi × i ) = -1 So if you make -1 negative, it become positive.
@RunstarHomer
@RunstarHomer 5 жыл бұрын
@@mundane3809 you are correct but the original comment was also correct. e^2πi = 1.
@mundane3809
@mundane3809 5 жыл бұрын
@@RunstarHomer oof yea it's actually correct. sorry for the mistake!
@alexsandroagustini714
@alexsandroagustini714 3 жыл бұрын
Him: Starts the video with 1+1=2 Me: *ok we are getting somewhere now
@science-y9209
@science-y9209 3 жыл бұрын
This was a great explanation
@G_sen_sei
@G_sen_sei 5 жыл бұрын
Very interesting calculation!
@hellopeter121
@hellopeter121 5 жыл бұрын
What Everybody knows : 1+1=2 What BPRP knows : 2=1+1 . . . . . What I know : 1+1=2 and 2=1+1 😇😇😇😇😇😇😇😇😇😇😇
@dev.imperatus6105
@dev.imperatus6105 5 жыл бұрын
Hmmm ive got an easier way when you use 1 + 1 instead of 2 Here is how I do according to you: (x^2+3x+2)(x^2+3x+1) =(x^2+3x)^2 +2 then √((x^2+3x)^2 +2) = x^2+3x+1
@XWurstbrotX
@XWurstbrotX 5 жыл бұрын
You can't solve squareroots of sums like that, eventhought your result is correct.
@carterwoodson8818
@carterwoodson8818 3 жыл бұрын
@4:15 wow I did not see it coming! Really good thank you!
@SpongeDude8
@SpongeDude8 5 жыл бұрын
More impressed with how someone came up with the question
@user-fr5cm7gs2m
@user-fr5cm7gs2m 5 жыл бұрын
Молодец! Хорошо объясняет, все понятно. Спасибо
@akhmadsw54
@akhmadsw54 5 жыл бұрын
Ага, он знаток
@LiegeNorth
@LiegeNorth 3 жыл бұрын
this guy is a genius!
@rahuldambo
@rahuldambo 5 жыл бұрын
Thats reall nicee man!!
@Geo25rey
@Geo25rey 3 жыл бұрын
I need to start a tradition of watching this video every year. It's just that good
@DriffPL
@DriffPL 5 жыл бұрын
I think you forgot about the absolute value; Square root of a 2nd power produces absolute value result because both positive and negative values are true.
@bttfish
@bttfish 5 жыл бұрын
Dunkoro it is obvious that the number inside the square root is positive,so ignore the absolute value symbol
@enzoTHEferrari
@enzoTHEferrari 5 жыл бұрын
I understood everything until the bit at 4:35 - 5:04 What do you mean by "factoring out"?
@AE-rg5rc
@AE-rg5rc 5 жыл бұрын
When a number repeats itself in an addition you can factor it out, basically do the inverse of distributive property. So we have x²+3x+1 repeating in both therms. You can factor it out and you will be left with x²+3x+1 ( x²+3x +1), equivalent to x²+3x+1( x²+3x) + x²+3x+1 (1)
@leif1075
@leif1075 5 жыл бұрын
@@AE-rg5rc but thats just squaring it and you don't have two of the sake expression..you don't jave twobx squared plus 3x plus 2 you only,have one
@ViratKohli-jj3wj
@ViratKohli-jj3wj 4 жыл бұрын
@@leif1075 please Learn some math, this is for grade 6 atleast in asian countries.
@leif1075
@leif1075 4 жыл бұрын
@@ViratKohli-jj3wj I know some math, thanks very much..I had a valid question
@vudomath
@vudomath 4 жыл бұрын
At 3:45, you could also treat the first factor as (x^2+3x+1-1) so together with the second factor you have (x^2+3x+1-1)(x^2+3x+1+1) = difference of squares ((x^2+3x+1)^2 - 1. Plus the extra 1 on the outside you get the perfect square.
@mesballo2224
@mesballo2224 3 жыл бұрын
Your way to solve this is pretty AWESOME!! First I multiplied all together, i got x^4 + 6x^3 + 11x^2 + 6x + 1 then i calculate this polynomial for x=1 x=2 x=3 ....all the time i got a square!! I was really surprise!! I didn't expect x(x+1)(x+2)(x+3)+1 to be a perfect square for all x at all!!! This is incredible!! Thanks for sharing your knowledge you are very inspiring to me
Dear Tejas, challenge ACCOMPLISHED! (Speed run, Uncut)
4:24
blackpenredpen
Рет қаралды 1,1 МЛН
are you tired of the a^b vs b^a questions?
12:42
blackpenredpen
Рет қаралды 922 М.
Василиса наняла личного массажиста 😂 #shorts
00:22
Денис Кукояка
Рет қаралды 5 МЛН
Precalculus teacher vs WolframAlpha student
11:27
blackpenredpen
Рет қаралды 614 М.
The hardest problem on the hardest test
11:15
3Blue1Brown
Рет қаралды 15 МЛН
Why do calculators get this wrong? (We don't know!)
12:19
Stand-up Maths
Рет қаралды 2,1 МЛН
5 Levels Of “No Answer" (when should we use what?)
24:50
blackpenredpen
Рет қаралды 412 М.
believe in the math, not wolframalpha
14:50
blackpenredpen
Рет қаралды 1,1 МЛН
Cambridge Mathematician Reacts to 'Animation vs Math'
28:35
Ellie Sleightholm
Рет қаралды 290 М.
Solving sin(x)^sin(x)=2
10:46
blackpenredpen
Рет қаралды 395 М.
What Is The Most Complicated Lock Pattern?
27:29
Dr. Zye
Рет қаралды 1,3 МЛН
Василиса наняла личного массажиста 😂 #shorts
00:22
Денис Кукояка
Рет қаралды 5 МЛН