SOLUTION: Solve the following exponential equation. e^x+e^-x=5 The​ solution(s) is/are ?

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Question 1039591: Solve the following exponential equation.
e^x+e^-x=5
The​ solution(s) is/are ?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
e^x+e^-x=5
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Sub u for e^X
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U + 1/U = 5
u^2 + 1 = 5u
u^2 - 5u + 1 = 0
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Solve the quadratic for u, then sub e^x for u.
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PS
(e^x + e^-x)/2 = cosh(x)
e^x + e^-x = 2.5
x = cosh-1(2.5)
x =~ 1.566799