- #1
callmelish
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Homework Statement
"Find dy/dx at the given point by using implicit differentiation"
x2y + y2x = -2 at (2, -1)
and
(x+y)3 = x3 + y3
Homework Equations
The Attempt at a Solution
1) x2(dy/dx) + y(2x) + y2(1) + 2y(dy/dx)(x) = -2
x2(dy/dx) + 2xy + y2 + 2xy(dy/dx) = -2
dy/dx(x2 + 2xy) = 2xy + y2 -2
dy/dx = (2xy + y2 -2)/(x2 + 2xy)
dy/dx at (2, -1) = (2*2*-1 - 2)/(22 + 2*2*-1)
= 0/0 = 0
The first one has me confused, and since the second one is similar I didn't want to attempt it in case I'm completely wrong.