Question

If y = -10 x^3 - 7 x, determine \frac{dy}{dt} when x = -4 and \frac{dx}{dt} = -1 .

\frac{dy}{dt} =

Answer 1

dy/dt = -30x^2*(dx/dt) - 7*(dx/dt)

so when x=-4 and dx/dt=-1,

dy/dt = -30(-4)^2*(-1) - 7*(-1)

Answer 2

thankd