# Homework Help: Parametric equations and finding tangents from circles

1. Mar 4, 2010

### xllx

1. The problem statement, all variables and given/known data
A circle has the parametric equations:
x=1+2cos$$\theta$$
y=3+2sin$$\theta$$

dy/dx= -1/tan$$\theta$$

Find the tangent equation at the point with parameter $$\theta$$
2. Relevant equations
y-y1=m(x-x1)

3. The attempt at a solution
I've tried putting dy/dx in as the gradient and then x1 and y1 as the parametric equations but i seem to come up with some really long equation that im sure isnt right.

Any help at all would be greatly appreciated. Many thanks.

2. Mar 4, 2010

### Mentallic

You mean you don't think this is right?:

$$y-3-2sin\theta=-cot\theta(x-1-2cos\theta)$$

Because it is :tongue: