ClearAll;
$DefaultFont = {"Times-Roman",12};
Needs["Graphics`Graphics`"];

xmax = 3; eticks = {0, 0.5, 1}; lticks = {0, 1, 2, 3};

expplot = Plot[1/(E^x),{x,0,xmax},
		AxesLabel -> {"x","y"},
		PlotLabel -> "(a) y = q(x) = 1/exp(x)",
		AxesOrigin->{-0.15,-0.05},
		Ticks->{lticks,eticks}];
logplot = Plot[Log[1/x],{x,1,1/E^xmax},
		AxesLabel -> {"y","x"},
		PlotLabel -> "(b) x = r(y) = ln(1/y)",
		AxesOrigin->{-0.05,-0.15},
		Ticks->{eticks,lticks}];
Show[GraphicsArray[{{expplot},{logplot}}],PlotLabel -> "Figure 7.5"]