y=f{g[h(p(x))]}y'=f'(g)g'(h)h'(p)p'(x)y'=1/cos(arctan(sinx)) *(-sin(arctan(sinx))*cosx/(1+sinx^2)= -tan(arctan(sinx))*cosx/(1+sinx^2)=-sinxcosx/(1+sinx^2)