# implicit diff.

• Oct 9th 2007, 06:51 PM
kwivo
implicit diff.
Ok, the question is: Find dy/dx by implicit differentiation.
(x^2)(y^2) + x sin y = 7

I tried and didn't get it right.

So, I used product rule first for (x^2)(y^2) and the same for xsiny.

(x^2)(2y dy/dx) + (y^2)(2x) + x(cosy dy/dx)+ siny = 0

For the part with the cosy dy/dx, I wasn't sure if I did that right. Should I have the dy/dx there like that? Is there anything else wrong from this point on?
• Oct 9th 2007, 06:54 PM
Jhevon
Quote:

Originally Posted by kwivo
Ok, the question is: Find dy/dx by implicit differentiation.
(x^2)(y^2) + x sin y = 7

I tried and didn't get it right.

So, I used product rule first for (x^2)(y^2) and the same for xsiny.

(x^2)(2y dy/dx) + (y^2)(2x) + x(cosy dy/dx)+ siny = 0

For the part with the cosy dy/dx, I wasn't sure if I did that right. Should I have the dy/dx there like that? Is there anything else wrong from this point on?

nope, this seems right so far. your mistake was probably made when you tried to solve for dy/dx

try again
• Oct 9th 2007, 07:26 PM
kwivo
Oh wait, I got it! Thanks anyway.