1)
а)f ' (x)=20x³-21x²-8x+8
f ' (-2)=-160-84+16+8=-244+24=-220
б)f ' (x)=sinx+xcosx
f ' (π/2)=1+(π/2)·0=1
2)
a)f ' (x)=((2x-8)'(4x+3)-(2x-8)(4x+3)')/(4x+3)²=(8x+6-8x+32)/(4x+3)²=38/(4x+3)²
б)f(x)=8·x^(3/5)
f ' (x)=(3/5)·8·x^(-2/5)=24/(5·⁵√(x²))
в)f ' (x)=(11^x)·ln11
г)f(x)=(4x-3)^(1/2)
f ' (x)=(1/2)·4·(1/√(4x-3))=2/√(4x-3)
3)y'=-sin(4x)·4
при х=π/2 y'=-4·0=0
4)y'=3x²-8x+5
3x²-8x+5=0
D=4
x=1
x=5/3
вроде так)