@@pk2712 yeah.. the alternative method gives that and all methods are important to build students..
@harrymatabal84484 күн бұрын
Excellent. But where did you get alpha from
@begechorimaths29754 күн бұрын
it's a mix up.. teeta is the alpha, thank you for the observation
@juanalfaro75226 күн бұрын
Let a/b = z. Then z+1 = 6*sqrt (z) --> (z+1) ^2 = 6^2 * z -> z^2 + 2z + 1 = 36z -> z^2 - 34z + 1 = 0 -> z^2 - 34z + 289 = 288 -> (z-17) ^2 = 2*14^2 -> z=a/b = 17 +/- 12*sqrt (2) [I.e., there are 2 solutions]
@mugaggaibrahim25107 күн бұрын
I disagree with your solution, sir. I have X = ±√(7+√13) and X = ±√(7-√13). They're supposed to be four roots
@user-il9cv5py3hКүн бұрын
they’re same answers
@sarantis40kalaitzis487 күн бұрын
Squring Both Sides. We get a^2+b^2+2ab=36ab so a^2+b^2=34ab. We DIVIDE Both Sides with b^2>0, hence (a^2/b^2)+(b^2/b^2)=34ab/b^2 so (a/b)^2+1=34*(a/b). Setting a/b=x we get x^2+1=34x so x^2-34x+1=0 so x=(34+ -sqrt(34^2-4))/2. Using trick of Difference of squares 34^2-2^2=(34+2)*(34-2)=36*32 so x= (34+ -6*sqrt32)/2= 17+ - 3sqrt32= 17+ - 3*sqrt16*sqrt2=17+ -12*sqrt2.
@pmac_8 күн бұрын
Easier to divide original equation by b giving: x² + 1 = 6 sqrt(x). Square both sides gives: x² - 34x +1 = 0 Simple.
@begechorimaths29757 күн бұрын
@@pmac_ Thank you!
@lechaiku8 күн бұрын
I've found the shortcut for such assignment: (a^3 + b ^3) /(a^3 + c^3); where a = b + c (a^3 + b ^3) /(a^3 + c^3) = (a +b) / (a +c) or (a^3 + c ^3) /(a^3 + b^3) = (a +c) / (a +b) for a = 97; b = 54; c = 43 (97^3 + 54 ^3) /(97^3 + 43^3) = (97 + 54) / (97+ 43) = 151/140
@begechorimaths29758 күн бұрын
@@lechaiku 👏🤝
@Direktorhkbergdahl7 күн бұрын
So, if I use this and set a = 97, b = 43, c = 54 b < c, so I use the second formula, which gives me (97 + 54)/(97 + 43) = 151/140, which is the same answer I get for a = 97, b = 54, c = 43 This implies that (97^3 + 54^3)/(97^3 + 43^3) = (97^3 + 43^3)/(97^3 + 54^3) Which is obviously incorrect Are you certain that it matters whether b>c or not?
@lechaiku7 күн бұрын
@@Direktorhkbergdahl You are in the right. What I meant was about the difference between the numerator and denominator. And I didn't change in the second formula an unknown "b" for "c". I have already corrected my previous comment. I will stay with that (a^3 + b ^3) /(a^3 + c^3) = (a +b) / (a +c) or (a^3 + c ^3) /(a^3 + b^3) = (a +c) / (a +b) Thank you for your hawk's eye and for noticing the slip.
(1 + R5)^3 = 1^3 + 3 R5 + 3 (R5)^2 + R5^3 = 1 + 3 R5 + 3 * 5 + 5 R5 = 16 + 8 R5, hence ((1+R5)/2)^3 = 2 + R5. (2+R5)^2 = 4 + 2 * 2 R5 + 5 = 9 + 4R5. (9 + 4R5)^2 = 81 + 9 * 4 * 2 R5 + 16 * 5 = 161 + 72 R5. Not such a nice solution, but only need binomal formulas for squaring and raising to the power 3, which I consider standard for 16 year old high school pupils
@begechorimaths297511 күн бұрын
@@zaphodbeeblebrox-fz5fh thank you for the observation..
@gregevgeni186412 күн бұрын
63+26=89
@user-ls8yt7nu7p12 күн бұрын
161+72√5
@begechorimaths297511 күн бұрын
@@user-ls8yt7nu7p thank you... just noticed the mistake at the very last step..
@user-cd7cn7hs7t11 күн бұрын
Agree!
@wuchinren12 күн бұрын
because 1/(x(x+4))=(1/4)(1/x-1/(x+4)), then 1/5+1/45+1/117+1/221+1/357+1/525 =(1/4)(1/1-1/5+1/5-1/9+1/9-1/13+1/13-1/17+1/17-1/21+1/21-1/25) =(1/4)(1/1-1/25) =6/25
@satyapriyagogula833413 күн бұрын
Good simplification sir
@MrRight-ht8hz14 күн бұрын
It is queer that 221 = 13 x 7. But I know that 13 x 7 = 91 So great an error is swooning
@ronbannon14 күн бұрын
Clear the fraction and let a=x^2-6 and b=x. You'll get a much simpler problem. The solution will be a nested root but will de-nest nicely.
@ManojkantSamal14 күн бұрын
*=read as square root 1/5=1/(1×5)=1_(1/5)=1-(1/5)=4/5 Similarly 1/45=1/(5×9)=1/5 - 1 /9=4/45 1/525=1/21 -1/25 The given series will be 1/4(1- 1/25) 1/4(24/25)=6/25 *(6/25)=*6/5
@Ohlukei14 күн бұрын
n=20
@thichhochoi76614 күн бұрын
Use 1/(9x5)=(1/5-1/9)/4 and 1/(9x13)=(1/9-1/13)/4, .... You will end up = (1-1/25)/4 = 6/25.
@thichhochoi76614 күн бұрын
Math Olympiad? for 1st grader?
@begechorimaths297514 күн бұрын
@@thichhochoi766 😯😁
@lechaiku15 күн бұрын
Another approach : x/21 + x/77 + x/165 + x/285 = 200 x/(3*7) + x(7*11) + x(15*11) +x (15*19) We can use that trick: Observe that the difference between both factors in each denominators is 4 (it's our D) so, we can use the multiplication of 1/D by the difference between the smallest factor and the biggest one divided by product of ab. a = 3; b = 19 ------> (b - a) / (ab) and D = 4 ---------------> 1/D 1/D [(b-a)/ab x/4(19 - 3)/ 3*19 = 200 x/4(16/57) = 200 4x / 57 = 200 x = 50*57 x = 2850 This very useful concept is based on identity: 1/a - 1/b = b-a/ ab and 1/ab = [(1/a) - (1/b)] (1/ (b-a)
@begechorimaths297515 күн бұрын
@@lechaiku 👊👊👊👏👏
@ShadowWarrior27715 күн бұрын
this also proves 36=16 if you expand (4-5)^2=(6-5)^2 WOAH!!!
@begechorimaths297515 күн бұрын
@@ShadowWarrior277 😁
@user-wj1qb3qu1y15 күн бұрын
No substitution (x²-x-6)²+(x²+x-6)²=6x² (x²+x-6-x²+x+6)²+2(x²+x-6)(x²-x-6)=6x² 4x²+2(x²-4)(x²-9)-6x²=0 ÷2 x⁴-14x²+36=0 ⇒(x²-7)²=13 x=±sqr(7±sqr13) By the way your voice is similar to affrican people You from affrica? My greeting to you
@begechorimaths297515 күн бұрын
@@user-wj1qb3qu1y yeah I am an African.. thank you brother
Yes. He did. The other roots are x≈±1.84 thus x≈±3.26 😅
@yakupbuyankara590315 күн бұрын
(6^(1/2))/5.
@jairuscastelino106016 күн бұрын
root a^2 = +-a; ya went wrong there...
@harrymatabal844816 күн бұрын
You can stand on your head your head and whistle through your backside 1+1can never be 3.neither can you divide by 0. Don't teach wrong things. Why don't you use sandpaper instead of toilet paper 😂😂😂😂
@begechorimaths297516 күн бұрын
@@harrymatabal8448 😀😃😁😁 thank you for watching, the aim is for you to watch and catch fun... hahahaha
@harrymatabal844817 күн бұрын
Bhoat acha. You much be from India.
@begechorimaths297517 күн бұрын
😁🙏
@harrymatabal844817 күн бұрын
Thanks for writing down the rules of exponents. We must be really dumb
@harrymatabal844818 күн бұрын
Magic. So cool
@begechorimaths297518 күн бұрын
@@harrymatabal8448 🙏🙏
@SrisailamNavuluri16 күн бұрын
1/5+1/5×9+1/9×13+1/13×17+1/17×21+1/21×25 =1/5+1/4(1/5-1/9+1/9-1/13+1/13-1/17+1/17-1/21+1/21-1/25) =1/5+1/4(1/5-1/25) =1/5+1/4(5-1)/25=1/5+1/25=5/25+1/25=6/25 Answer is √6/5
@sy814619 күн бұрын
Thank you for explaining. I have a question. If we use " f(x)≧0 for √f(x) ", x=2 should be rejected because all values "inside of the √ " are negative. If x=2 is one of the solutions, I guess the problem admits complex numbers. (: The reason of rejection is not "Not Real.") ・・・ If x=2, (the left side) = 3√2 i + 2√2 i and (the right side) = 5√2 i . Thus, it can satisfy the equation (, but it is not real numbers.) And, even if the complexed numbers are admitted, if x=-5/3, (the left side) = (4√17)/3 i + (√17)/3 i and (the right side) = (√17) i . Thus, it does NOT satisfy the equation. Therefore, I guess the reason why x=-5/3 is rejected in this video is a little different. <<<<< Anyway, if the rejecting reason is "Not Real", x=2 should be rejected (as well as x=-5/3). On the other hand, if the rejecting reason is "Not Satisfy the given Equation" ( but complex number is OK ), only x=-5/3 is rejected. >>>>> (My question is "which condition is the original problem requiring?" )
@Birol73119 күн бұрын
Interesting question, thank you very much for sharing 🙏👌
There are an infinite number of solutions if they are not integers. Rearrange the equation to create a formula for a. Substitute Arbitrary values for b, to get the corresponding value of a for which this equation is satisfied
@rafalablamowicz791921 күн бұрын
a=24 and b =96
@williamniver606321 күн бұрын
Incorrect, I am afraid. The problem specifies that b is an "odd number". 96 doesn't satisfy the condition, so your answer fails. Admittedly, the odd number requirement is seen only at the start of the videoclip, but not on the initial screenshot.
@user-ee7nw2rx9s21 күн бұрын
Делим на х и умножить на 36 (х-6/х-1)^2+(х-6/х+1)^2=6 Легко видно что а=х-6/х Тогда (а+1)^2+(а-1)^2=6 а^2+1=3 а=sqrt 2 или а= - sqrt 2 Дальнейшее просто Два простых квадратных уравнений х-6/х-sqrt2=0 или х-6/х+sqrt 2=0 Решение которых не составит труда Решение от силы 3 - 4 минуты, но не 10 как на видео. Если это часть теста, то вы потеряли 6 минут просто так
Horrible video. You would have obtained a polynomial of degree 4 and you only found 2 solutions. You cannot disregard the plus or minus sign in this case.
@begechorimaths297521 күн бұрын
@@moeberry8226 thanks for the feedback
@ronbannon14 күн бұрын
That's a bit harsh. I, too, solved this problem and knew I was looking for four roots. It is easy to get lost in algebra. Although I did not watch the entire video, I did see that he correctly arrived at two of the solutions. Again, we eventually all get lost in the algebra, and I suggest graphing this problem to see that four real roots are present.
@begechorimaths297514 күн бұрын
@@ronbannon Thank you so much 🙏🙏, I really appreciate your kind words
@DarkTitan-wm5zn21 күн бұрын
A fairly easy question. I solved it just in my head by using the natural logarithm after the factorization.It will give us the same result and in a more direct way n³=-1. But, first the question does not specify whether n is a complex or a real number. Because in the set of real numbers there exists a unique solution which is -1. But in the set of complexe numbers there exist 3, which are -1,-j,-j² in this case, as it is -1 and not 1 (the negative of the cubic root of unity of a complexe number). In any case good exercise