`y = cosec(3x) + cot(3x)`

`y' = -3*cosec(3x)*cot(3x) - 3*cosec^2(3x)`

y' = `-3*cosex(pi/2)*cot(pi/2) - 3*cosec^2(pi/2)`

`or, y' = -3*1*0 - 3*1`

`or, y' = -3`

``

`y = cosec(3x) + cot(3x)`

`y' = -3*cosec(3x)*cot(3x) - 3*cosec^2(3x)`

y' = `-3*cosex(pi/2)*cot(pi/2) - 3*cosec^2(pi/2)`

`or, y' = -3*1*0 - 3*1`

`or, y' = -3`

``