
Implicit Differentiation
I'm currently studying maths, and need help with the following question:
$\displaystyle x^4 + 4yx  2y^5 = 3$
I'm new to implicit differentiation, and have followed the book closely on this one (using dy/dx notation, which I am also new to). I've been using matlab to verify my answers, but it hasn't matched with this one.
My answer $\displaystyle dy/dx = \frac{(4x^3 + 4y + 4x)}{10y^4}$
Matlab answer = $\displaystyle 4x^3 + 4y$
Can someone please help me with this?

When you want an error spotted in your work, it's best to show what you did step by step. Otherwise I have no idea where you made a mistake and the only way to help you is to type out a full solution myself, which is time consuming.
Can you post your work?

That makes sense... working out step by step below:
Step One
$\displaystyle \frac{d}{dx}(x^4+4xy2y^5) = \frac{d}{dx}(3)$
Next step: Calculating the derivative bit by bit
$\displaystyle \frac{d}{dx}(x^4) + \frac{d}{dx}(4xy)  \frac{d}{dx}(2y^5) = 0$
Now...finding derivatives (including product rule regarding d/dx(4xy))
$\displaystyle 4x^3 + \frac{d}{dx}(4x)y + 4x\frac{d}{dx}(y)  \frac{dy}{dx}\frac{d}{dy}(2y^5) = 0$
this is where I think I get stuck...most likely regarding product rule and dy/dx style notation (what is the difference between $\displaystyle \frac{d}{dx} \frac{dy}{dx} \frac{d}{dy}$ and $\displaystyle \frac{dx}{dy}$?
$\displaystyle 4x^3 + 4y + 4x\frac{d}{dx}(y)  \frac{dy}{dx}10y^4 = 0$
$\displaystyle 4x^3 + 4y + 4x \frac{dy}{dx}10x^4 = 0$
$\displaystyle \frac{dy}{dx} = \frac{4x^3 + 4y + 4x}{10y^4}$
Also, when using dy/dx notation I've noticed my uniwritten coursebook uses brackets after dy/dx to denote underived components of the equation, then once they've been differentiated the brackets are removed to signify so. Am I right in saying this? (is that the rule of thumb?)