3= 2*(e^x - e^-x)
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Mohammad Sulaiman Stanekzai
2017년 12월 21일
답변: Mohammad Sulaiman Stanekzai
2017년 12월 24일
How to solve this equation to find x? Thanks in advance
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채택된 답변
Birdman
2017년 12월 21일
편집: Birdman
2017년 12월 21일
syms x
eq=3==2*(exp(x)-exp(-x));
sol=vpasolve(eq)
If you solve it with solve command, you will obtain two roots, but one of them is a complex solution. Therefore, I directly solved it with vpasolve. But also see the solution for the solve command. The result is 0.6932.
sol=solve(eq)
추가 답변 (4개)
Torsten
2017년 12월 21일
Substitute
e^x = y.
This leads to
y - 1/y = 3/2
or
y^2 - 3/2*y - 1 = 0.
Thus
y = 3/4 + sqrt(25/16) = 2.
Then
x = log(y) = log(2).
Or use
xsol = solve(3==2*(exp(x)-exp(-x)),x)
Best wishes
Torsten.
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Star Strider
2017년 12월 21일
Much simpler, because your equation is equivalent to 4*sinh(x):
xarg = @(y) asinh(y/4)
Result = xarg(3)
Result =
0.693147180559945
Even the anonymous function is not necessary. I added it to convenience.
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