x^2+xy+y^2=12

dy/dx = -(2x+y)/(x+2y)

Am I right?

No, its mathS.

use the S, its english!!

aye.

better?

Cheers sam.

42

Well it's been about 15 years since I did that sort of stuff but I came up with same answer as you.

No. It's 12.

x=2, y=2

could be 12
could x=2, y=2

Have a look for yourself

RealMan, your answer is one of the two correct answers. The other is shown on travis' link

Yeah, depends on what you differentiate with respect to. Question didn't state which, so I assumed x.

Been a while since I did this but you're differentiating y with respect to x. Treat all the y's as a constant.

dy/dx [ x^2 + xy + y^2 – 12 = 0]

= 2x + y

All Travis's link has done is show you a solution to the equation. I have a sneaky feeling that I might be barking up the wrong tree here, it's been about 5 years since I differentiated anything.

Treat all the y's as a constant.

I have a sneaky feeling that I might be barking up the wrong tree here

Yep.

🙂

D'oh.