i got 2 Functions Y(x)=lxl^3 f(x)=x-1
1) Prove that Y can be Differentiable In point 0
2) use the information from ur Proof In 1 to Prove that the Function l(x-1)l^3
are Differentiable In point 1
thanks for helping.
Now compute the limit from the left and the limit from the right separately. They both give 0, showing that the derivative of Y at 0 exists and is equal to 0.
For the second one use the derivative theorem about the composition of 2 functions.
If you need clarification on the right and left hand limits let me know.