How do you integrate int e^(sqrt(2x)) by parts?

1 Answer
Jan 19, 2017

inte^sqrt(2x)dx=e^sqrt(2x)(sqrt(2x)-1)+C

Explanation:

I=inte^(sqrt(2x))dx

Let t=sqrt(2x). This implies that 1/2t^2=x, which we differentiate to show that dx=tcolor(white).dt. Then:

I=inte^t(tcolor(white).dt)=intte^tdt

We will use integration by parts now, which takes the form intudv=uv-intvdu. For intte^tdt, let:

{(u=t" "=>" "du=dt),(dv=e^tdt" "=>" "v=e^t):}

Then:

I=uv-intvdu

I=te^t-inte^tdt

I=te^t-e^t+C

I=e^t(t-1)+C

Returning to x from t=sqrt(2x):

I=e^sqrt(2x)(sqrt(2x)-1)+C