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# C4 Implicit Differentiation Watch

1. I'm trying to differentiate with respect to x. I know I could multiply by the denominator, then differentiate, but I've decided to use the quotient rule, and for some reason I can't get to the right answer.

After simplifying, I get:

Am I along the right lines, or have I done something completely wrong?
2. I really wouldn't advise the quotient rule with two variables on the bottom. I don't know what would happen but I can't imagine it's nice.
3. Well, it should work, should it not?
4. Could you expand your steps to see exactly what you did?

I'm not entirely sure what you've done.

5. Then simplified slightly further..
6. you forgot the 2 from 2y
7. As far as i can tell you can't differentiate with respect to x at the very start because when you differentiate the "x" on the left hand side you end up with dx/dx instead of dy/dx
Just wondering, how did you put that formula up on your post?
8. Code:
x=2y/(x2-y)

x3-yx=2y

x3-yx-2y=0

differentiate --> 3x2-(dy/dx)(x)-y-2dy/dx=0

3x2-y=dy/dx(x+2)

dy/dx=(3x2-y)/(x+2)
I'm new here so I'm not sure how to show it as a formula or anything, but that's what I got!
9. (Original post by Brecon)
Code:
x=2y/(x2-y)

x3-yx=2y

x3-yx-2y=0

differentiate --> 3x2-(dy/dx)(x)-y-2dy/dx=0

3x2-y=dy/dx(x+2)

dy/dx=(3x2-y)/(x+2)
I'm new here so I'm not sure how to show it as a formula or anything, but that's what I got!
I got this also and comparing the values when x=1, y=0 from ours with the OP's I think his is wrong.
10. (Original post by Pheylan)

Thanks .
11. No problem, hope that helped out a little :P This was one of my favourite topics last year.

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