71-72. One-sided derivatives The right-sided and left-sided derivatives of a function at a point a are given by f'- (a) - lim flath) - f(a) and f'_(a) - lim flat h) - f(a) respectively, provided these limits exist. The h h derivative S'(a) exists if and only if S' +(a) = S'_(a). a. Sketch the following functions. b. Compute f'_(a) and f'_(a) at the given point a. c. Is f continuous at a? Is f differentiable at a? 4 - :2 72. f(*) = 2x+1 ifx >1 ;0=1