## imagreencat Group Title Hey guys! I would just like to ask if my partial differentiating is correct. f(x,y)=xy (sin (4yx^2)) fyx = sin 4yx^2 + (8yx^2)(cos 4yx^2) + (12yx^2)(cos 4yx^2) - 32(x^4)(y^2)(sin 4yx^2) Thanks! 2 years ago 2 years ago

1. ash2326 Group Title

You have differentiated with respect to x or y?

2. imagreencat Group Title

Well, fyx. So I first diff with respect to y then with respect to x. :)

3. TuringTest Group Title

it's the mixed derivative? let me check...

4. ash2326 Group Title

Ok :)

5. TuringTest Group Title

$f_x=y\sin(4yx^2)+8x^2y^2\sin(4x^2y)\cos(4x^2y)$I'm typing it out so we can all see if I make a mistake...

6. imagreencat Group Title

Fy first. :) Then diff Fy with respect to x.

7. TuringTest Group Title

the order shouldn't matter I don't think$f_{xy}=\sin(4yx^2)+4yx^2\cos(4yx^2)+\frac{\partial}{\partial y}[8x^2y^2\sin(4x^2y)\cos(4x^2y)]$

8. imagreencat Group Title

Actually in some cases the order does not matter. But in others, it does. Anyway, thank you turing test! :)

9. TuringTest Group Title

oh but I have a 16...

10. TuringTest Group Title

I'll do it the other way on paper to see if that makes a diff

11. TuringTest Group Title

ok I redid it the other way and got the same answer as you sorry for the confusion

12. imagreencat Group Title

It's okay Turing Test. I'm sorry for taking some of your time. :))) But, thanks again. I appreciate your effort.

13. TuringTest Group Title

no it's my fault for messing up the first time you're welcome