How do you integrate #int xsec^2x# by integration by parts method?

1 Answer
Aug 1, 2016

#xtanx + ln|cosx|+C#

Explanation:

#int xsec^2x dx#

Integration by parts: #int f(x)g'(x) dx = f(x)g(x) - int f'(x)g(x) dx#

In this example: #f(x)=x -> f'(x) = 1#
and #g'(x)=sec^2x -> g(x) = tanx#

Therefore: #int xsec^2x dx = xtanx - int(1*tanx) dx#

#int xsec^2x dx = xtanx - int tanx dx#

#= xtanx + ln|cosx|+C# (Standard integral)