Помогите с 238 и 237(в,г)

238)a)f'(x)=sin'(x+x-/4)=(cos(x+x-/4))*

(3x+1)
f'(0)=cos/4=2/2
b)f('x)=tg'(x+/6)=(1/cos(x+/6))*2x
f'(0)=0

237)f'(x)=(tg(2-3x))'=

3tg(2-3x)*(1/cos(2-3x))*
(2-3x)'=-9tg(2-3x)/cos(2-3x)


f'(x)=(ctg(2x-1))'=

4*ctg(2x-1)*(-1/sin(2x-1)

*(2x-1)'=

-8ctg(2x-1)/sin(2x-1)