A Nice Math Olympiad Algebra Problem | How to solve!!
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- เผยแพร่เมื่อ 8 พ.ค. 2024
- In todays video, I will be teaching you how to solve an interesting problem. Make sure to like, subscribe, and also comment any questions or video ideas you may have relating to math!
#maths #exponents #mathematics #mathstricks #mathchallenge #algebra #equation #problem #challenge #Olympiad #MathOlympiad
There is also a solution where x is approximately equal to 1.0224.
Also where x is approximately equal to -0.97902.
when the comments solve better than the video
You are not solving the equation, just finding one solution which is, let’s say, intuitive. But this method will not always work, so it’s not a valid way to solve the equation.
There are, in fact, two other solutions.
Use the Lambert W function W(■*e^■) = ■
2^x = x^32
ln(2^x) = ln(x^32)
x*ln(2) = 32*ln|x| ===> two cases
1st case: x > 0
x*ln(2) = 32*ln(x)
ln(x)*x^(-1) = ln(2)/32
ln(x)*e^ln(x^(-1)) = ln(2)/32
ln(x)*e^(-ln(x)) = ln(2)/32
-ln(x)*e^(-ln(x)) = -ln(2)/32
W(-ln(x)*e^(-ln(x))) = W(-ln(2)/32)
-ln(x) = W(-ln(2)/32)
ln(x) = -W(-ln(2)/32)
x = e^(-W(-ln(2)/32)) ===> -1/e < -ln(2)/32 < 0 ===> 2 real solutions
x1 = e^(-W_[0](-ln(2)/32)) = 1.0223929402057803206527516798494005683768365119132864517728278977...
in WolframAlpha: e^(-productlog(0,-ln(2)/32))
x2 = e^(-W_[-1](-ln(2)/32)) = 265
in WolframAlpha: e^(-productlog(-1,-ln(2)/32))
2nd case: x < 0
x*ln(2) = 32*ln(-x)
ln(-x)*x^(-1) = ln(2)/32
-ln(-x)*x^(-1) = -ln(2)/32
ln(-x)*(-x)^(-1) = -ln(2)/32
ln(-x)*e^ln((-x)^(-1)) = -ln(2)/32
ln(-x)*e^(-ln(-x)) = -ln(2)/32
-ln(-x)*e^(-ln(-x)) = ln(2)/32
W(-ln(-x)*e^(-ln(-x))) = W(ln(2)/32)
-ln(-x) = W(ln(2)/32)
ln(-x) = -W(ln(2)/32)
-x = e^(-W(ln(2)/32))
x = -e^(-W(ln(2)/32)) ===> ln(2)/32 > 0 ===> 1 real solution
x3 = -e^(-W_[0](ln(2)/32)) = -0.979016934957784612322582550011650068748090048886011676265377083...
in WolframAlpha: -e^(-productlog(0,ln(2)/32))