h(r)=1-r^2/2-r^3 find h'(1)

h(r) = (1 - r^2)/(2 - r^3)

h'(r) = [(-2r)(2 - r^3) - (1 - r^2)(-3r^2)]/(2 - r^3)^2

h'(1) = [(-2)(1) - (0)(-3)]/(2-1)^2 = -2