# Implicit Differentiation

• Apr 11th 2010, 12:25 AM
Mitch281008
Implicit Differentiation
Hey everybody,

I have found a question in a textbook saying to use implicit differentiation to find dy/dx when x^5 + 3y^3 + 5 = 3x^6y^5.

i get as far as differentiating and i cant get the answer.

any help?

Mitch :)
• Apr 11th 2010, 12:36 AM
mr fantastic
Quote:

Originally Posted by Mitch281008
Hey everybody,

I have found a question in a textbook saying to use implicit differentiation to find dy/dx when x^5 + 3y^3 + 5 = 3x^6y^5.

i get as far as differentiating and i cant get the answer.

any help?

Mitch :)

Please show all your working and say where exactly you get stuck.
• Apr 11th 2010, 01:44 AM
Mitch281008
ive done the differentiating on the right hand side. i tried on the left but its not right.
ive got 5x^4 + 9y^2 = ......
and im not sure what to do in terms of the implicit differentiation.

thanks
Mitch
• Apr 11th 2010, 02:51 AM
mr fantastic
Quote:

Originally Posted by Mitch281008
ive done the differentiating on the right hand side. i tried on the left but its not right.
ive got 5x^4 + 9y^2 = ......
and im not sure what to do in terms of the implicit differentiation.

thanks
Mitch

The derivative of y^3 with respect to x is got using the chain rule: $\frac{d y^3}{dx} = \frac{dy^3}{dy} \cdot \frac{dy}{dx}$. If you could not do this, I have my doubts that you did the right hand side correctly.