How do you integrate int (x+4)e^(-5x) by integration by parts method?

1 Answer
Feb 23, 2017

The answer is =-((5x+21))/25e^(-5x)+C

Explanation:

The integration by parts is

intu'vdx=uv-intuv'dx

Here, we have

u'=e^(-5x), =>, u=-e^(-5x)/5

v=x+4, =>, v'=1

Therefore,

int(x+4)e^(-5x)dx=-(x+4)/5e^(-5x)-int-e^(-5x)/5dx

=-((x+4))/5e^(-5x)-e^(-5x)/25+C

=-((5x+21))/25e^(-5x)+C