Question

y=(1+cosx)/(sinx) 求dy?

Answer 1

dy=[(1+cosx)'*sinx-(1+cosx)*(sinx)']/(sinx)^2

=(-sinx*sinx-(1+cosx)cosx)/(sinx)^2

=(-sin^2x-cosx-cos^2x)/(sinx)^2

=(-1-cosx)/(sinx)^2