Chapter 2 - Differentiation - 2.6 Exercises - Page 153: 5

a) -8 cm/sec b) 0 cm/sec c) 8 cm/sec

$y = 2x^2 + 1$ $\frac{dy}{dt} = 4x \frac{dx}{dt}$ If dx/dt = 2 a) when x = -1 then $\frac{dy}{dt} = 4(-1)(2) = -8cm/s$ b) when x = 0 then $\frac{dy}{dt} = 4(0)(2) = 0 cm/sec$ c) when x = 1 then $\frac{dy}{dt} = 4(1)(2) = 8 cm/sec$