Question

Find y' if x^2 + y^2 = 10.

a. 2x + 2y = 0
b. 10 − 2x − 2y
c. negative x over y
d. 10 − x over y

Answer 1

x^2 + y^2 = 10

take the partial derivative

2x + 2y dy/dx =0

subtract 2x from each side

2y dy/dx = -2x

divide by 2y

dy/dx = -2x /2y

dy/dx = -x/y