Find dy/dx by Substituting r for y and Theta for x | Simple Implicit Problem

[Minihoudini]

Homework Statement

substituting r for y and theta for x as it will be easier to read

find dy/dx if r=x^2 tan(2x)

I don't know the answer

Homework Equations

The Attempt at a Solution

d/dx (y) = d/dx [x^2 tan(2x)]

dy/dx = dx/dx [2x] d/dx [tan (2x)]

dy/dx = 2x sec^2 (2x) (2)

dy/dx = 4x sec^2 (2x)

its wrong though

 

[Mark44]

Homework Statement

substituting r for y and theta for x as it will be easier to read

find dy/dx if r=x^2 tan(2x)

I don't know the answer

Homework Equations

The Attempt at a Solution

d/dx (y) = d/dx [x^2 tan(2x)]

dy/dx = dx/dx [2x] d/dx [tan (2x)]

The line above is wrong. x^2 * tan(2x) is a product, so you need to use the product rule. You are using the chain rule correctly, below.

dy/dx = 2x sec^2 (2x) (2)

dy/dx = 4x sec^2 (2x)

its wrong though