Question

Eliminate the parameter.

x = 3 cos t, y = 3 sin t

Answer 1

http://openstudy.com/updates/54c5811ae4b0158439ec16e5

Answer 2

hmm anyhow, same procedure
solve for "t" onthe 1st equation

Answer 3

We will take advantage of the Pythagorean trig identity to get...


\[\Large x^2 + y^2 = (3\cos(t))^2+(3\sin(t))^2\]


\[\Large x^2 + y^2 = 9\cos^2(t)+9\sin^2(t)\]


\[\Large x^2 + y^2 = 9(\cos^2(t)+\sin^2(t))\]


\[\Large x^2 + y^2 = 9(1)\]


\[\Large x^2 + y^2 = 9\]

Notice how I used the identity \(\Large \cos^2(t)+\sin^2(t)=1\) (which is true for all real numbers t).

Answer 4

actaully.. is a trig.. ok