Eliminate the parameter t & graph (trig)

[maskofeowyn]

x=-cost & y=cost

I know that cost = -x and that cost = y. I know I need to use a trig function to change these so that I can solve it so that I can graph it. I'm confused as to which function to use. Please help! Thank you.

 

[pka]

Surely you can see that: $\displaystyle y = - x.$

 

[soroban]

Surely you can see that: $\displaystyle y = - x.$ . . . Correct!

But since $\displaystyle \,-1\:\leq \:\cos t \:\leq\:1,\;x$ and $\displaystyle y$ are similarly limited.

The graph is a line segment from $\displaystyle (-1,1)$ to $\displaystyle (1,-1)$