CALCULUS - DIFFERENTIABILITY

[simple helm]

How did you get these answers?

[pale mortar]

I've got different numbers and I think mine should be correct as I checked it

Also I think it should be $0 \leq x \leq 3$ and not $0 < x \leq 3$

[charred spruce]

adonhs

[pale mortar]

If the function should be twice differentiable then the LHS limit must be equal to the RHS limit at the critical points x = 0 and x = 3 as depending on the coefficients you can have a jump point or not