(a) Generate an overlay plot for plotting three lines

\[\begin{aligned}& y_{1}=\sin t \\& y_{2}=t \\& y_{3}=t-\frac{t^{3}}{3 !}+\frac{t^{5}}{5 !}+\frac{t^{7}}{7 !} \quad 0 \leq t \leq 2 \pi\end{aligned}\]

Use (i) the plot command

(ii) the hold command

(iii) the line command

(b) Use the functions for plotting $x-y$ data given in Table $6.5(b)$ for plotting the following functions.

\[\begin{array}{ll}\text { (i) } f(t)=t \cos t & 0 \leq t \leq 10 \pi \\\text { (ii) } x=e^{t} & \\\quad y=100+e^{3 t} & 0 \leq t \leq 2 \pi\end{array}\]