Question #602c5

1 Answer
Oct 14, 2016

I will assume there is no error in the question.

Explanation:

#f(x) = root(3)(3x-6+5) = root(3)(3x-1) = (3x-1)^(1/3)#

#f'(x) = 1/3 (3x-1)^(-2/3)d/dx(3x-1)#

# = 1/(3(3x-1)^2/3) * 3#

# = 1/(root(3)(3x-1))^2 #

#f'(x)# exists for all #x# except solutions to #(root(3)(3x-1))^2 =0#

#f'(x)# exists for all #x# except #1/3#

If the argument of the 3rd root should be #3x^2-6x+5#, then the function is differentiable at every real number.

Because #3x^2-6x+5 = 0# has no real number solution.