Calculus
posted by Jane .
Answer ?  impicit differentiation
Find dy/dx & d^2y/dx^2
y^2  x^2 = 2
is the answer dy/dx=x/y; d^2y/dx^2=
y^2x^2/y^2

2y(dy/dx)  2x = 0
dy/dx = 2x/(2y) = x/y
y'' = (y(1)  x(y'))/y^2
= (y  x(x/y))/y^2
= (y^2  x^2)/y^3
you had y^2 at the bottom of your y''
did you notice that there was a y in the denominator of your top?