Option 1. is obtained by eliminating the parameter.
Step-by-step explanation:
Step 1:
We have that and
Take as equation 1.
Assume is equation 2.
We need to determine a value that is equivalent to t so it can be substituted in equation 2.
Step 2:
If we square equation 1, we get
So we have a value that can replace t, so we substitute this is equation 2.
so
which is the first option.