y=sinxx+cosx, then dydx=?
xcosx−sinx+1(x+cosx)2
Here u(x)=sin x, v(x)=x + cos x.
dydx=(x+cosx)d(sinx)dx−sinxd(x+cosx)dx(x+cosx)2
(Using quotient rule)
=(x+cosx)cosx−sinx(1−sinx)(x+cosx)2=xcosx+cos2x−sinx+sin2x(x+cosx)2
=xcosx−sinx+sin2x+cos2x(x+cosx)2=xcosx−sinx+1(x+cosx)2