`h(t) = 2(cot(pit + 2))^2 = 2cot^2(pit + 2)`

`h'(t) = 4cot(pit+2)*[-cosec^2(pit+2)]*pi`

`or, h'(t) = -4pi*cot(pit+2)*cosec^2(pit+2)`

``

`h(t) = 2(cot(pit + 2))^2 = 2cot^2(pit + 2)`

`h'(t) = 4cot(pit+2)*[-cosec^2(pit+2)]*pi`

`or, h'(t) = -4pi*cot(pit+2)*cosec^2(pit+2)`

``