ClearAll;
$DefaultFont = {"Times-Roman",10};
Needs["Graphics`Graphics`"];
p0 = Plot[1,{t,0,1.4}];
p1 = Plot[t,{t,0,1.4}];
p2 = Plot[t^2,{t,0,1.4}];
p3 = Plot[t^3,{t,0,1.4}];
poly0 = Show[Graphics[{GrayLevel[0.35],Rectangle[{0.5,0},{0.9,1}]}],
			  p0,Axes->True,AspectRatio->Automatic,
			  PlotRange->{{0,1.4},{0,1.4}},
			  AxesLabel->{"  x","y"}, 
			  Ticks ->{{{0.5,"a"},{0.9,"t"}},{0,1}},
			  PlotLabel ->"(a) y = g(x)"];
poly1 = Show[Graphics[{{GrayLevel[0.65],
			  Polygon[{{0,0},{0.5,0},{0.5,0.5}}]},
			  {GrayLevel[0.35],
			  Polygon[{{0.5,0},{0.9,0},{0.9,0.9},{0.5,0.5}}]}}],p1,
			  Axes->True,
			  AspectRatio->Automatic,
			  PlotRange->{{0,1.4},{0,1.4}},
			  AxesLabel->{"  x","y"}, 
			  Ticks ->{{{0.5,"a"},{0.9,"t"}},{0}},
			  PlotLabel ->"(b) y = r(x)"];
poly2 = Show[Graphics[{{GrayLevel[0.65],
			  Polygon[Join[Table[{0.005k,(0.005k)^2},{k,0,100}],{{0.5,0}}]]},
			  {GrayLevel[0.35],
			  Polygon[Join[Table[{0.5 + 0.004k,(0.5 + 0.004k)^2},{k,0,100}],{{0.9,0},{0.5,0}}]]}}],p2,
			  Axes->True,
			  AspectRatio->Automatic,
			  PlotRange->{{0,1.4},{0,1.4}},
			  AxesLabel->{"  x","y"}, 
			  Ticks ->{{{0.5,"a"},{0.9,"t"}},{0}},
			  PlotLabel ->"(c) y = w(x)"];
poly3 = Show[Graphics[{{GrayLevel[0.65],
			  Polygon[Join[Table[{0.005k,(0.005k)^3},{k,0,100}],{{0.5,0}}]]},
			  {GrayLevel[0.35],
			  Polygon[Join[Table[{0.5 + 0.004k,(0.5 + 0.004k)^3},{k,0,100}],{{0.9,0},{0.5,0}}]]}}],p3,
			  Axes->True,
			  AspectRatio->Automatic,
			  PlotRange->{{0,1.4},{0,1.4}},
			  AxesLabel->{"  x","y"}, 
			  Ticks ->{{{0.5,"a"},{0.9,"t"}},{0}},
			  PlotLabel ->"(d) y = z(x)"];
Show[GraphicsArray[{{poly0,poly1},{poly2,poly3}}],PlotLabel->"Figure 11.2"]