In the 1st u have to know that d/dx tanx =sec2x
so
multiply num and denom by sec4x
upper sec2x and neeche sec4x+tanxsec4x aa jaega
then put tanx=t and sec2xdx=dt
neeche sec4x ko write in terms of tan x and substitute to get ur answer
1.
cos2x/(1+tanx)=sec2x/[sec4x(1+tanx)]=sec2x/[(1+tan2x)2(1+tanx)
I don't have any better approach
2.
[(x/e)x+(e/x)x]lnx=(x/e)xlnx+(e/x)xlnx
taking first one
(x/e)xlnx dx
taking (x/e)x=t
then (x/e)xlnx dx=dt
∫(x/e)xlnx dx=∫dt=t+C=(x/e)x+C
Similarly fond for other
http://www.goiit.com/posts/list/integration-integration-plz-can-anyone-help-me-77629.htm#379975
In the 1st u have to know that d/dx tanx =sec2x
so
multiply num and denom by sec4x
upper sec2x and neeche sec4x+tanxsec4x aa jaega
then put tanx=t and sec2xdx=dt
neeche sec4x ko write in terms of tan x and substitute to get ur answer