1 Area of triangle = × × ℎ ℎ 2 1 1 = × 5 × 5 = 12 2 2 Calculate the area under the curve, 1 3 2 Area of grey = ∫ ( + 1) 2 −1 1 3 3 = [ + ] 2 3 −1 1 3 3 (−1) 3 = [ + 3 − + 1] 2 3 3 32