Comute f(x) of

a) f(x) = sinxcosx / sinx + cosx
b) f(x) = (1-x^2) / (1+x+x^2)
c) f(x) = x^7 secx

2 answers

Proofread you question before posting it.
Not familiar with the different modes of transportation of functions if you meant commute.
Just use the normal product and chain rules, with the chain rule:

f=uv, f' = u'v+uv'
f=u/v, f' = (u'v-uv')/v^2

Just take it a step at a time; you know how to get the derivatives of the various function involved. If you get stuck, come back with your work so far.