Question

Did I do this right? xy=4 Find dy/dt when x=8 given dx/dt=10

Answer 1

dx/dt*y + x**dy/dt = 0

10y + 8 dy/dt = 0

8 dy/dt = -10y

dy/dt = -5/4 y

Answer 2

i dont think so hold on let me do it on paper

Answer 3

dx/dt * y + x * dy/dt = 0
you did that part correctly

Answer 4

the only thing you need is to solve for y

Answer 5

Solve for y? why

Answer 6

dy/dt = -5/4 y , you can plug in y, since we know that x*y = 4 , and x = 8 , that means

Answer 7

8*y = 4 ,
y = 4/8

Answer 8

ooooooooooh

Answer 9

so dy/dt= -5?

Answer 10

I mean -5/8