For each of the following signals write an expression for $z(t)$ using unit$-$step function and sketch it$.z(t)=x(t)+y(t),$ where $x(t)=t^2+1$ for tin$[-1,1]$ and $x(t)=0$ otherwise; $y(t)=1$ for tin$[0,1]$ and $y(t)=0$ otherwise. Can i have the sketch hand wrritten thanks