Let, I=int2xe^(3x)dx rArr I=2intxe^(3x)dxI=∫2xe3xdx⇒I=2∫xe3xdx.
To find II, we will use the following Rule of Integration by Parts :
intuvdx=uintvdx-int{(du)/dxintvdx}dx∫uvdx=u∫vdx−∫{dudx∫vdx}dx.
We take, u=x, so, (du)/dx=1, &, v=e^(3x), so, intvdx=1/3e^(3x)u=x,so,dudx=1,&,v=e3x,so,∫vdx=13e3x. So,
I=x*1/3e^(3x)-int{1*1/3e^(3x)}dxI=x⋅13e3x−∫{1⋅13e3x}dx
=x/3e^(3x)-1/3inte^(3x)dx=x3e3x−13∫e3xdx
=x/3e^(3x)-1/3*1/3e^(3x)=x3e3x−13⋅13e3x
:. I = 1/9*(3x-1)*e^(3x)+C.