(i) Write the Maxima command to plot the curves y=x,y=x2,y=x3 where x - and y-range are determined by 1x1 and 20y 20. All the graphs should appear on the same gnuplot window. (ii) Write a Maxima command to plot the surface z=x2y2 on the region {D=(x,y)R22x2,2y2}