Consider the function x²+2x-1 if x ≤ -1 f(x) = 3/8x 2x+4 3 if − 1 < x <1 - if x > 1 (a) To determine whether f is differentiable at x = -1, we compute lim h→0+ 2/3 - ƒ(−1 + h) − f(−1) h lim h→0+ lim h→0- 0 ƒ(−1 + h) − f(−1) h = lim h→0- = (b) To determine whether f is differentiable at x = 0, we compute lim h→0 f(h) - f(0) h lim h→0 (c) To determine whether f is differentiable at x = 1, we compute lim h→0+ lim h→0- f(1+ h) − f(1) h - f(1+h) − f(1) h - lim h→0+ lim h→0- = 2/3 ||