# New equation

1. Oct 5, 2009

### squenshl

The parabola y = x2 is rotated anti-clockwise about the origin through the angle 30o. What is the new equation of the new curve (relative to the standard basis)?

2. Oct 5, 2009

### Office_Shredder

Staff Emeritus
If you have a point (x,x2) and you rotate it by 30 degrees around the origin what does it become?

3. Oct 5, 2009

### HallsofIvy

Staff Emeritus
And you can rotate a point (x,y) through an angle $\theta$ about the origin by the matrix multiplication
$$\begin{bmatrix}cos(\theta) & -sin(\theta) \\ sin(\theta) & cos(\theta)\end{bmatrix}\begin{bmatrix}x \\ y\end{bmatrix}$$.