c$)$ Eliminate the parameter $\backslash ($ t $\backslash )$ to find a Cartesian equation of the curve in $\backslash ($ x $\backslash )$ and $\backslash ($ y $\backslash ).$

d$)$ If the Cartesian equation from c$)$ needs restrictions on $\backslash ($ x $\backslash )$ and$/$or $\backslash ($ y $\backslash )$ to describe the curve from b$),$ enter these restrictions as inequalities $($separated by a comma if necessary$).$ If restrictions are implied in the Cartesian equation, enter 'None'. If you need to enter $\backslash (\backslash$leq $\backslash ),$ type $\backslash (\{\}^\{\backslash$circcirc$\}\backslash ).$ To enter $\backslash (\backslash$geq $\backslash ),$ type $"\backslash (>==^\{\backslash$prime $\backslash$prime$\}\backslash ).$