I'm going to try to retype my attempted work in a more readable manner.
I used the quotient rule to get:
\frac{(1+xtanx)\frac{d}{dx}(sinxsecx)-(sinxsecx)\ast\frac{d}{dx}(1+xtanx)}{(1+xtanx)}
Then went on trying to cancel out the top since the denominator was already the value i was trying...
Find y^{I} (sinxsecx)/1+xtanx The supplied answer is 1/(1+xtanx)^{2}
I got stuck with an extra x on top at the end. Where did I mess up at?
y^{I}(sinxsecx)/1+xtanx = [1+xtanx*f^{I}(sinxsecx)-sinxsecx*f^{I}(1+xtanx)]/(1+xtanx)^{2} =...