Question

If 4x^2-y=100 and dy/dt =-6, find dx/dt when x=1.

Answer 1

Differentiate.

Answer 2

Can you give me a step-by-step?

Answer 3

First find dy/dx and put x = 1 and you will get a numerical value.

dy/dx = dy/dt x dt/dx = (dy/dt) / (dx/dt)
So dx/dt = (dy/dt) / (dy/dx) --- (1)

When x = 1, dy/dt = -6 and you know dyx/dx at x = 1 from step 1.

Substitute in (1) and compute dx/dt