A Nice Math Olympiad Question
11:34
2 сағат бұрын
Пікірлер
@에스피-z2g
@에스피-z2g 2 сағат бұрын
x^(1/2+1/4+1/8+1/16+1/32)=x^(31/32) =8 x=8^(32/31)
@wes9627
@wes9627 19 сағат бұрын
a=5/2+c & b=5/2-c; (5/2+c)(5/2-c)=8; c^2=25/4-32/4=-7/4; c=±i√7/2; a=(5±i√7)/2 & b=(5∓i√7)/2
@Kwalliteht
@Kwalliteht Күн бұрын
√(x*√(x*√(x*(√x*√x))))=8 x*√(x*√(x*(√(x*√x)))=8^2 x^3*√(x*(√(x*√x))=8^4 x^7*√(x*√x)=8^8 x^15*√x=8^16 x^31=8^32 x=8^(32/31) x=8.555037588568538...
@ericasi4562
@ericasi4562 Күн бұрын
Это шутка?
@juergenilse3259
@juergenilse3259 2 күн бұрын
Substitute t=10^x and recall that 100^x=(10^x)^^2 and 1000^x=(10^x)^3. Than you get t+t^2=t^3 t^3-t^2-t=0 t*(t^2-t-1)=0 t=0 or t^2-t--1=0 t=0 or t=(1+sqrt(5)/2 or t=(1+sqrt(5)/2 Reember, tht t=10^x>0, so t=0 and t=(1-sqrt(5) willll be rejected So we get 10^x=(1+sqrt(5)/2 x=llog((1+sqrt(5))/2)
@Italianor01
@Italianor01 3 күн бұрын
a+b=100 ab=1000. 90+10=10] 9p.10=90] Imrightmaster?? a+b=c cb=d cb=1000 100×10=1000❤❤😂😊🎉
@DebasishGayen-l7h
@DebasishGayen-l7h 3 күн бұрын
You have taken long time shortcut methods are there
@ОльгаЛебедева-ю6ы
@ОльгаЛебедева-ю6ы 3 күн бұрын
Ответ - 5. Практически сразу.
@prollysine
@prollysine 3 күн бұрын
x^3+/-x^2+/-x-64=0 , (x-4)(x^2+4x+16)=0 , x^2+4x+16=0 , x=(-4+/-V(16-64))/2 , x=(-4+/-i*V(48))/2 , x=(-4+/-i*4V(3))/2 , 1 -4 solu , x= 4 , -2+i*2V3 , -2-i*2V3 , 4 -16 16 -64
@ElenaRastgar
@ElenaRastgar 3 күн бұрын
a=2
@AlexanderSemashkevich
@AlexanderSemashkevich 3 күн бұрын
x=4 or x= -2±2i×sqrt3
@AlexanderSemashkevich
@AlexanderSemashkevich 3 күн бұрын
2^x=a a³-a=120 5³-5=125-5=120 a=5 2^x=5 x=log5/log2= x≈0.699/0.301≈2.322 Deviation is about 0.0003 8^2.322-2^2.323≈120.018
@rarocon
@rarocon 3 күн бұрын
8 + 2 = 10
@veikkoritvaniemi7627
@veikkoritvaniemi7627 4 күн бұрын
Wrong solution. Should be square -48 not -58.
@joliettraveler
@joliettraveler Күн бұрын
spotted that right away.
@AvikDey-z6y
@AvikDey-z6y 4 күн бұрын
(a-b) ^2=(a+b) ^2 - 4ab =10000-4000 =6000 =100×60 Or (a-b) =10√60 Now a+b=100 a-b=10√60 Next 2a =100+10√60 Or a=50+5√60 and b=50-5√60
@uroojmehdi5801
@uroojmehdi5801 4 күн бұрын
Gud sir thankx my dear
@chaklai4663
@chaklai4663 4 күн бұрын
Wonderful and respected. 🙏💖
@ОлександрПрадеус
@ОлександрПрадеус 4 күн бұрын
-5. 25-(-125)=150
@1234larry1
@1234larry1 4 күн бұрын
An easy problem, but I wonder why you chose such large numbers that are prime for the solution set. It’s just makes the arithmetic a little harder, but I don’t see the point.
@chaklai4663
@chaklai4663 4 күн бұрын
I saw too many maths KZbin show how to solve arithmetics like this, but no one will choose a larger prime numbers. Just curious, I am sorry.🫡
@erictu1678
@erictu1678 4 күн бұрын
my answer is x=51/2 1/2 and y = 49/ 2 1/2; do not know how to type root of 2 square; any catch for this problem?
@wes9627
@wes9627 4 күн бұрын
Best Trick? a=97/2+c, b=97/2-c, (97/2+c)(97/2-c)=997, c^2=97^2/4-997=5421/4, a=(97+√5421)/2, b=(97-√5421)/2
@alexniklas8777
@alexniklas8777 4 күн бұрын
Мало знаков, добавить ещё 5😅😅😅
@subratabiswas2502
@subratabiswas2502 4 күн бұрын
√(x√x........)=x^(31/32) ; so, x^(31/32)=8 ; i,e x=8^(32/31) ; i,e x=2^(3×32/31) ; i,e x= 2^(96/31)
@DesertScorpionKSA
@DesertScorpionKSA 4 күн бұрын
I have to study my log rules.
@TheFarmanimalfriend
@TheFarmanimalfriend 5 күн бұрын
well done! 😃
@hakade5846
@hakade5846 5 күн бұрын
Is it really Math OLYMPIAD Problem?? REALLY??
@AlphaSorceror
@AlphaSorceror 2 күн бұрын
They call everything Olympiad problem. These are just indices.
@에스피-z2g
@에스피-z2g 2 сағат бұрын
I don't think so.
@AlphaSorceror
@AlphaSorceror 2 сағат бұрын
Just count the number of square roots. There are 5 so the LHS index power must be 1 / 2^5) = 1/32 X^(1/32) = 2^3 Then solve. What nonsense that this is Olympiad?
@srinivasanrao1033
@srinivasanrao1033 5 күн бұрын
Very nice solutions
@Mathsfocus8610
@Mathsfocus8610 5 күн бұрын
Thank you! Cheers!
@nenaud
@nenaud 5 күн бұрын
writing correctly your signs, your letters and your numbers will ease the understanding of your demonstration thanks for this help anyway
@07Pietruszka1957
@07Pietruszka1957 5 күн бұрын
You lost third answer x=-0.766665
@abeljacobi4221
@abeljacobi4221 5 күн бұрын
Right, there aren't only integer solutions. x ≈ -0.766665 (or with a few more decimals x ≈ -0.766664695962123093111)
@werbone
@werbone 6 күн бұрын
I wish people would stop using Olympiad to attract views of very straightforward problems.
@Салют-я5с
@Салют-я5с 6 күн бұрын
а=-5
@chaklai4663
@chaklai4663 6 күн бұрын
a+b=97 ab=997 Could you solve it.🤔
@Mathsfocus8610
@Mathsfocus8610 5 күн бұрын
Be expecting that in my next video tomorrow
@羁绊在可视宇宙之外
@羁绊在可视宇宙之外 6 күн бұрын
2or3😂
@stpat7614
@stpat7614 6 күн бұрын
Isn't there a complex solution? 9^x + 3^x = 20 (3^2)^x + 3^x = 20 3^(2 * x) + 3^x = 20 3^(x * 2) + 3^x = 20 (3^x)^2 + 3^x = 20 Let u = 3^x (3^x)^2 + 3^x = 20 => u^2 + u - 20 = 20 - 20 => u^2 + u - 20 = 0 => 1 * u^2 + 1 * u + (-20) = 0 Let a = 1, b = 1, c = -20 1 * u^2 + 1 * u + (-20) = 0 => a * u^2 + b * u + c = 0 u = (-b +/- sqrt[b^2 - 4 * a * c]) / (2 * a) u = (-1 +/- sqrt[1^2 - 4 * 1 * (-20)]) / (2 * 1) u = (-1 +/- sqrt[1 + 80]) / (2) u = (-1 +/- sqrt[81]) / 2 u = (-1 +/- sqrt[9^2]) / 2 u = (-1 +/- 9) / 2 u = (-1 + 9) / 2, or u = (-1 - 9) / 2 u = 8 / 2, or u = -10 / 2 u = 4, or u = -5 Remember, u = 3^x u = 4, or u = -5 => 3^x = 4, or 3^x = -5 Suppose 3^x = 4 3^x = 4 log(3^x) = log(4) x * log(3) = log(4) x * log(3) / log(3) = log(4) / log(3) x * log_3(3) = log_3(4) x * 1 = log_3(2^2) x = 2 * log_3(2) Suppose 3^x = -5 3^x = -5 ln(3^x) = ln(-5) x * ln(3) = ln(-1 * 5) x * ln(3) / ln(3) = ln(-1 * 5) / ln(3) x * log_3(3) = (ln[-1] + ln[5]) / ln(3) x * 1 = ln(-1) / ln(3) + ln(5) / ln(3) x = ln(e^[i * tau / 2]) / ln(3) + log_3(5) x = (i * tau / 2) * ln(e) / ln(3) + log_3(5) x = (i * tau / 2) * 1 / ln(3) + log_3(5) x = i * tau / (2 * ln[3]) + log_3(5) x1 = 2 * log_3(2) x2 = i * tau / (2 * ln[3]) + log_3(5)
@oliviercresson1643
@oliviercresson1643 6 күн бұрын
Expliquer vous
@kommentar1709
@kommentar1709 6 күн бұрын
From equation (1) we get a = 11-b. Insert this into (2) to get (11-b)b = 111 -> 11b - b² = 111 -> b²-11b-111 = 0. Now solve for b1,2 by applying the quadratic formula to get b1 = 33/2 and b2 = -11/2. Insert either solution into equation (1) to find that in case of b1, a1 would become -11/2, while in case of b2, a2 would calculate as 33/2. Hence there are two reciprocal solutions for real numbers of a and b: [a1,b1] = [-11/2,33/2] and [a2,b2] = [33/2,-11/2].
@tonyennis1787
@tonyennis1787 4 күн бұрын
Your answers are incorrect. 16.5 * -5.5 <> 111
@1234larry1
@1234larry1 6 күн бұрын
Not meaning to criticize, because I’m sure your videos are valuable for people who are just beginning to understand algebra, but can you occasionally put videos which are more challenging? Thank you.
@quertzvonmaskevt1583
@quertzvonmaskevt1583 6 күн бұрын
Where did you get 15?
@1234larry1
@1234larry1 6 күн бұрын
When you factor 6000, two factors in which one is a “perfect square” are 400 times 15, 400 being the perfect square.
@Mathsfocus8610
@Mathsfocus8610 6 күн бұрын
400 x 15 = 6000 ✓ 400=20, multiply by √15
@varshiniexim3823
@varshiniexim3823 6 күн бұрын
Excellent. Great job ❤
@Ghorgolla
@Ghorgolla 7 күн бұрын
Thanks mate! :)
@prollysine
@prollysine 7 күн бұрын
let u=3^x , u^2+u-20=0 , (u-4)(u+5)=0 , u= 4 , / -5 < 0 not a solu for x/ 3^x=4 , x=log4/log3 , 1 -4 test 9^x+3^x=16+4 , --> 20 , OK , 5 -20
@stpat7614
@stpat7614 7 күн бұрын
a + b = 11 a + b - b = 11 - b a = 11 - b ab = 111 (11 - b)b = 111 11b - b^2 = 111 11b - b^2 - 111 = 111 - 111 -b^2 + 11b - 111 = 0 b^2 - 11b + 111 = 0 b = (-[-11] +/- sqrt[(-11)^2 - 4*1*111]) / (2 * 1) b = (11 +/- sqrt[121 - 444]) / (2) b = (11 +/- sqrt[-333]) / 2 b = (11 +/- sqrt[-1 * 3 * 3 * 37]) / 2 b = (11 +/- sqrt[-1] * sqrt[3^2] * sqrt[37]) / 2 b = (11 +/- i * 3 * sqrt[37]) / 2 b = (11 + i * 3 * sqrt[37]) / 2, or b = (11 - i * 3 * sqrt[37]) / 2 b1 = (11 + i * 3 * sqrt[37]) / 2 b2 = (11 - i * 3 * sqrt[37]) / 2 a1 = 11 - b1 a1 = 11 - (11 + i * 3 * sqrt[37]) / 2 a1 = 11 * 2 / 2 - (11 + i * 3 * sqrt[37]) / 2 a1 = 22 / 2 - (11 + i * 3 * sqrt[37]) / 2 a1 = 22 / 2 + (-11 - i * 3 * sqrt[37]) / 2 a1 = ([22 - 11] - i * 3 * sqrt[37]) / 2 a1 = (11 - i * 3 * sqrt[37]) / 2 a2 = 11 - b2 a2 = 11 - (11 - i * 3 * sqrt[37]) / 2 a2 = 11 + (-11 + i * 3 * sqrt[37]) / 2 a2 = 11 * 2 / 2 + (-11 + i * 3 * sqrt[37]) / 2 a2 = 22 / 2 + (-11 + i * 3 * sqrt[37]) / 2 a2 = ([22 - 11] + i * 3 * sqrt[37]) / 2 a2 = (11 + i * 3 * sqrt[37]) / 2 { (a1, b1), (a2, b2) } = { ([11 - i * 3 * sqrt(37)] / 2, [11 + i * 3 * sqrt(37)] / 2), ([11 + i * 3 * sqrt(37)] / 2, [11 - i * 3 * sqrt(37)] / 2) }
@gerhardb1227
@gerhardb1227 8 күн бұрын
subst u^32 = sqrt(x) => u^31= 8 u = 8^(1/31) resubstitution: sqrt(x) = 8^(32/31) x = 8^(64/62) = 8^(32/31)
@lionelfischer8240
@lionelfischer8240 8 күн бұрын
Trivial try = -5. Finished in 30 s.
@wyterminator3736
@wyterminator3736 8 күн бұрын
Another method.. SQRT(3^x * SQRT( (9^x) * SQRT(81^x ) ) ) = 81 = 3 ^ 4 where SQRT(81 ^ X) = SQRT(9 ^ 2x) = 9^x SQRT( 3^x * SQRT( 9^x * 9^x ) ) = 3 ^ 4 where SQRT( 9^x * 9^x ) ) = 9 ^ x = 3 ^ 2x SQRT( 3 ^ x * 3 ^ 2x ) = 3 ^ 4 SQRT( 3 ^ 3x ) = 3 ^ 4 where SQRT( 3 ^ 3x ) = 3 ^ (3/2)x 3 ^ (3/2)x = 3 ^ 4 where 3x/2 = 4 multiply each side by 2/3. x = 8/3
@jeffreyhudale5633
@jeffreyhudale5633 8 күн бұрын
262143
@oscargraveland
@oscargraveland 8 күн бұрын
You still need to verify x2,y2
@AVR0709
@AVR0709 9 күн бұрын
The answer is Log(φ )/Log(5). I think you have done a mistake somewhere.
@nasrullahhusnan2289
@nasrullahhusnan2289 9 күн бұрын
(5^x)+(25^x)=125^x [(5³)^x]-[(5²)^x]-(5^x)=0 (5^x)³-(5^x)²-(5^x)=0 Divide by (5^x)≠0: (5^x)²-(5^x)-1=0, a quadratic equation in 5^x: 5^x≠½[1±sqrt(5)] As 5^x can't be negative, 5^x=ß is golden ratio --> x=[log(ß)]/log(5)
@nasrullahhusnan2289
@nasrullahhusnan2289 9 күн бұрын
What you get are three pairs of real numbers, not of natural number.
@Mathsfocus8610
@Mathsfocus8610 6 күн бұрын
That's why it was concluded that no solution. Thanks