[SOLVED] [Vector Calculus]: Max, Min of magnitude of acceleration

Ok so I have a vector function:

**r**(t)=$\displaystyle <3cos(t) , 2sin(t)>$

Alright so I have to find the Max and Min for the magnitude of the acceleration.

The steps I was undergoing were:

1. I found the velocity vector **v**(t)=$\displaystyle <-3sin(t) , 2cos(t)>$

2. I found the acceleration vector **a**(t)=$\displaystyle <-3cos(t) , -2sin(t)>$

and this is where I'm a little confused, so I have to find the function for the magnitude of **a**(t) and then derive it, find the critical points and those will be my max and min. But the problem is that when I find the magnitude of acceleration it gives me a constant. (sin^2 + cos^2 = 1)

But that's the equation for an ellipse so the acceleration is not constant... so what am i doing wrong?

EDIT: Oh crap I just realized what a dumb mistake I was making, the magnitude is not a constant, the coefficients are different, sin squared and cos squared can't be factored.