Нужна помощььььььь!!!!

A) $y' = (ctg3x)' + (3 x^{4)'} - (21x)' = - \frac{1}{Sin ^{2}x } *(3x)' + 12 x^{3} - 21 = = - \frac{3}{Sin^{2}x } + 12 x^{3} - 21$
2) $y' = ((4x + 3) ^{6} )' - (33)' = 6(4x+3) ^{5} *(4x+3)' = 24(4x+3) ^{5}$
3) $y' = \frac{(4+2x)'*3 - (4+2x)*3'}{9} = \frac{6-4-2x}{9} = \frac{2-2x}{9}$
4) $y' = 1/2(Cos2x)' + (x ^{-4} )'- (4 x^{2})' - ( \frac{ \pi }{2})' = - 1/2Sin2x*(2x)' - 4x ^{-5}$ - $8x = - Sin2x - 4x ^{-5} - 8x$