1.1 f'(x)=15x²-16x³+4x-3 f'(1)=15-16+4-3=0
1.2 f(x)=xctgx f'(x)=(uv)'=u'v+v'u u=x u'=1 v=ctgx v'=-1/sin²x
f'(x)=1*ctgx-x/sin²x f'(π/4)=1-(π/4)/(1/√2)²=1-2π/4=1-π/2
2a f'(u/v)=1/v²[u'v-v'u] u=3x-2 u'=3 v=2x+3 v'=2
f'(x)=1/(2x+3)²[3(2x+3)+2(3x-2)]
2b f(x)=7*x^6/7 f'(x)=7*6/7x^(6/7-1)=6x^(-1/7)=6/x^(1/7)
2c f(x)=√(6x+5) f'(x)=6/2√(6x+5) = 3/√(6x+5)