Find the critical number of the function: f(x)= x^8 -8x^7

Question

please help

Answer 1

To find the critical number(s), set the derivative of the function equal to zero.

 

f'(x) = 0

 

8x⁷ - 56x⁶ = 0

 

 

You can factor out 8x⁶.

 

8x⁶(x - 7) = 0

 

x = 0        and      x = 7

 

 

The critical numbers are    x=0     and     x=7.