The command grid on adds a grid to the plot. The resulting plot is shown in Fig. $4.$

Exercise $3$

Use the command plot $3(x,y,z)$ to plot the circular helix $x=5cos(7t),y=5sin(7t),z=9t,0t5.$

Add a grid to the plot using the command grid on$.$

NOTE: Use semicolon to suppress the output when you define the vectors $t,x,y$ and $z.$ Make sure you use enough points for your graph so that the resulting curve is nice and smooth.