Note that the derivative above holds for every point on the circle, and exists for
all y different from 0 (where the tangents to the circle are vertical).
Example 28 __
If x^2 − 2xy + 3 y^2 = 2, find .
SOLUTION:
Example 29 __
If x sin y = cos (x + y), find .
SOLUTION:
Example 30 __
Find and using implicit differentiation on the equation x 2 + y 2 = 1.
SOLUTION: