integrationWatch

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Thread starter 13 years ago
#1
Can someone show me how to do the following integration please:

∫e^x cosh x dx

Thanks
0
13 years ago
#2
Integrate by parts.
0
13 years ago
#3
Just use integration by parts where: f(x)=e^x and g'(x)=cosh x and thus g(x)=sinh x
0
13 years ago
#4
Or:
e^x cosh(x) = e^x (e^(x) + e^(-x))/2
= (e^(2x) + 1)/2

Which integrates to:
(0.5e^(2x) + x)/2 + C
0
13 years ago
#5
Integrating by parts doesn't work (although I suggested it above!). Use

e^x cosh(x) = (1/2)(e^(2x) + 1)
0
13 years ago
#6
(Original post by Retropmot)
you can't get the integral by parts but when u do it

I = int(e cosh x)

I = e sinh x - int(e sinh x)

I = e sinh x - e cosh x + I

0 = e(sinh x - cosh x) = -1

Which step isn't valid?
You forgot the constant of integration.
0
Thread starter 13 years ago
#7
Thanks
0
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