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# C4 Implicit Differentiation watch

1. For part of a question I need to diff. y(x + y)^2

Using the chain rule I got as follows:

2(x+y)(1+(dy/dx))

I'm fairly certain I'm right till that point, but then do I need to use the product rule to fully differentiate it? I don't understand how the first 'y' comes into play.

I'm sure it's simple but I'm at a loss!

Thank you to anyone who helps.
2. (Original post by DAstonClarke)

I'm fairly certain I'm right till that point, but then do I need to use the product rule to fully differentiate it?
yes
3. (Original post by TenOfThem)
yes
OK.

U = y & V = (x+y)^2

du/dx = dy/dx & V = 2(x+y)(1+(dy/dx)) (as prev. calculated)

That produces: (x+y)^2 . (dy/dx) + 2(x+y)(1+(dy/dx))

Correct?
4. (Original post by DAstonClarke)
OK.

U = y & V = (x+y)^2

du/dx = dy/dx & V = 2(x+y)(1+(dy/dx)) (as prev. calculated)

That produces: (x+y)^2 . (dy/dx) + 2(x+y)(1+(dy/dx))

Correct?
yep
5. (Original post by TenOfThem)
yep
Thank you! :]

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