Let y = 4 x 2 + 5 x + 3 . If Δ x = 0.4 at x = 2 , use linear approximation to estimate Δ y Δ y ≈

Question

Let . If  at , use linear approximation to estimate    

Answer 1

Δy ≈ dy = f'(2)Δx; f'(x) = 8x + 5; f'(2) = 8·2 + 5 = 21;

so, Δy ≈ 21·0.4 = 8.4