From what you know about the graphs of functions (i) through (v), pick out the one that is the derivative of f for x>0.

Question

Show your work.
f(x)=x ln x-x
i. y=sin x
ii. y=ln x
iii. y= x^(1/2)
iv. y=x^2
v. y=3x-1

Answer 1

f(x)=x ln x-x
f'(x) = x(1/x) + lnx - 1
= 1 + lnx - 1
= lnx