Velocity_x = 3cos3t - 3sint . How do you get x=3 when you put in t=0

This was the original problem:

Given the parametric equations for the position of an object, find the object’s velocity and speed at the given times and describe its motion.
x=3cost+sin3t
y=3sint+cos3t"



Velocity is the derivative of time, so we have

velocity_x = 3cos3t - 3sint
velocity_y = 3cost -3sin3t

A)
Just plug in t=0 and we get
velocity_x = 3
velocity_y = 3

This is part of a problem worked out. I don't know how x=3. I plugged into my nspire cx cas this:
3cos(3)0 - 3sin(0) and the answer I got was 0 not 3. What am I doing wrong?

You plugged it in wrong.

It would be:

3cos(3*0) - 3sin(0))

3 * 1 - 0
=3

cos0 = 1