Question

integrate cos(lnx)dx

Answer 1

use the sub u=ln(x)

Answer 2

\[du=\frac{dx}{x} \\ x du=dx \\ e^u du=dx \text{ since } u=\ln(x)\]

Answer 3

Then you should be able to use integration by parts.

Answer 4

@laith1995 ?

Answer 5

Thanks i solve it
it need integrate by part twice

Answer 6

u= cos(lnx) dv=dx
du=1/x*-sin(lnx) v=x
=xcos(lnx)-integrate x*1/x sin(lnx) dx
another integrate

Answer 7

@freckles

Answer 8

oh yeah
gj you just straight up integrating by parts it looks like
like it should go around again and you should be able to solve the equation for the integral(cos(ln(x))