How do I integrate (e^x)*(sinx)^2 ??
I know I need integration by parts.
If I choose e^x as my 'u' i get
e^x (sinx)^2 - integral of e^x 2sin(x)cos(x) dx
and I don't know how to solve that integral either
Maybe I picked the wrong 'u' though..
Thanks!
I know I need integration by parts.
If I choose e^x as my 'u' i get
e^x (sinx)^2 - integral of e^x 2sin(x)cos(x) dx
and I don't know how to solve that integral either
Maybe I picked the wrong 'u' though..
Thanks!
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Use an identity first. There is the half-angle identity
sin²(x) = ½ - ½cos(2x).
The integrand is then (1/2)e^x - (1/2)e^x cos(2x). The first term can be integrated straight away. The second term requires integration by parts.
With e^x cos(2x), integrate by parts twice until you get the same integral---with integrand e^x cos(2x)---on both sides of the equation with different coefficients. Then solve algebraically.
You can choose u = e^x each time you integrate by parts.
sin²(x) = ½ - ½cos(2x).
The integrand is then (1/2)e^x - (1/2)e^x cos(2x). The first term can be integrated straight away. The second term requires integration by parts.
With e^x cos(2x), integrate by parts twice until you get the same integral---with integrand e^x cos(2x)---on both sides of the equation with different coefficients. Then solve algebraically.
You can choose u = e^x each time you integrate by parts.