Stuck on another calculus question. It seems prettty simple but I can't seem to figure it out.

Draw the curve for

x=4 cos t

y=5 sen t

I plugged in values and drew hte curve with was pretty easy but i can't figure out the ecuation for the curve.

This is what i did so far:

x/4=cos t

y/5=sen t

t[0,180] (I couldn't find the pi symbol)

(x/4)^2=cos^2 t

(y/5)^2=sen^2 t

(x/4)^2+(y/5)^2=cos^2 t + sent^2 t

(x/4)^2+(y/5)^2 = 1

....from this is see a circle with radius 1 and center in th origin. But the curve i got from plugging in values is clearly a parabola.

any help???