а) f'(x)=3x^2-27
3x^2-27=0
x^2=9
x=±3
f'(x)>0 при х∈(-∞;-3)∨(3;+∞)
b) f'(x)=8x^3-1
8x^3-1=0
x^3=
x=
f'(x)>0 при х∈(;+∞)
c) f'(x)=3x^2-4
3x^2-4=0
x^2=
x=±
f'x>0 при х∈(-∞;-)∨(;+∞)
а) f'(x)=3x^2-27
3x^2-27=0
x^2=9
x=±3
f'(x)>0 при х∈(-∞;-3)∨(3;+∞)
b) f'(x)=8x^3-1
8x^3-1=0
x^3=
x=
f'(x)>0 при х∈(
;+∞)
c) f'(x)=3x^2-4
3x^2-4=0
x^2=
x=±
f'x>0 при х∈(-∞;-
)∨(
;+∞)