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implicit differentiation question.

omichael

how would I go about doing this question?
find the gradient of this
y^2 = 12x at point (3,6)

Reply 1

the bear

Original post by omichael

how would I go about doing this question?
find the gradient of this
y^2 = 12x at point (3,6)

so you can find dx/dy and then work with that.

Reply 2

omichael

Original post by the bear

so you can find dx/dy and then work with that.

I keep getting y=6 which is wrong.

Reply 3

the bear

did you manage to find dx/dy ?

Reply 4

RDKGames

Study Forum Helper

Original post by omichael

how would I go about doing this question?
find the gradient of this
y^2 = 12x at point (3,6)

Do you understand what to do to find the gradient??

Reply 5

omichael

Original post by the bear

did you manage to find dx/dy ?

This is how I found it.

Reply 6

the bear

Original post by omichael

This is how I found it.

yes that works.

Reply 7

RDKGames

Study Forum Helper

Original post by omichael

This is how I found it.

This isn't as clear, even though you reach the final derivative.

You should preferably do it by the following steps for clarity:

y^2=12x

\dfrac{d(y^2)}{dx}=\dfrac{d(12x)}{dx}

\dfrac{dy}{dx}\cdot \dfrac{d(y^2)}{dy} = 12

\dfrac{dy}{dx}\cdot 2y = 12

and so on...

Reply 8

omichael

Original post by the bear

yes that works.

its was a trick question it asked for the gradient but the answer is the equation of the tangent.

thanks for your help.

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