MATHEMATICS · Multi-part · AP · Calculus AB · Limits and Continuity · Limits and Continuity
Problem
For a real parameter a, consider the piecewise function
fa(x)={ax+x2,x,x≤0,x>0.
The value of fa(0) is determined by the first branch.
(1) Part 1: Determine all real values of a for which fa is continuous at x=0. Show all work.
(2) Part 2: For each value of a found in part (a), evaluate the left–hand and right–hand derivatives of fa at x=0. Decide whether fa is differentiable at x=0 and support your reasoning with appropriate limits.
(3) Part 3: Classify the type of non-differentiability you find in part (b) (corner, cusp, or vertical tangent) and explain your classification using the behavior of the derivative limits.