3= 2*(e^x - e^-x)
7 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Mohammad Sulaiman Stanekzai
le 21 Déc 2017
Réponse apportée : Mohammad Sulaiman Stanekzai
le 24 Déc 2017
How to solve this equation to find x? Thanks in advance
0 commentaires
Réponse acceptée
Birdman
le 21 Déc 2017
Modifié(e) : Birdman
le 21 Déc 2017
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)
Plus de réponses (4)
Torsten
le 21 Déc 2017
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.
0 commentaires
Star Strider
le 21 Déc 2017
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.
0 commentaires
Voir également
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!