These cells contain the code to generate this schematic offered above.

Input := 

p0 = ParametricPlot3D[{u,u,Sqrt[1 - u^2]}, {u,0,1},
	AxesLabel->{"x","y","z"},
	ViewPoint->{4.000, 0.730, 2.030},
	AspectRatio->Automatic]

Input := 

p1 = ParametricPlot3D[{Cos[t], 0, Sin[t]},{t,0, Pi/2},
	AxesLabel->{"x","y","z"},
	ViewPoint->{4.000, 0.730, 2.030},
	AspectRatio->Automatic]

Input := 

p2 = ParametricPlot3D[{t+1,Cos[t],0},{t,0, Pi/2},
	PlotRange->{{0,3},{0,1},{0,1}},
	ViewPoint->{4.000, 0.730, 2.030},
	AspectRatio->Automatic]

Input := 

p3 = Show[Graphics3D[{PointSize[.02],
	Point[{.8,0,Sqrt[1-.8^2]}],
	Point[{.8,.8,Sqrt[1-.8^2]}],
	Point[{.8,.8,0}],Point[{.8,0,0}],
	Line[{{0,0,0},{1,1,0}}],
	Line[{{1,0,0},{1,1,0}}],
	Line[{{.8,0,0},{.8,.8,0}}],
	Line[{{.8,0,Sqrt[1 - .8^2]},
		{.8,.8,Sqrt[1 - .8^2]}}],
	Line[{{.8,0,0},{.8,0,Sqrt[1 - .8^2]}}],
	Line[{{.8,.8,0},{.8,.8,Sqrt[1 - .8^2]}}],
	Line[{{0,0,0},{.8,0,Sqrt[1 - .8^2]}}],
	Line[{{.8,.8,0},{1,.8,0}}],
	Line[{{0,0,0},{3,0,0}}],
	Line[{{0,0,0},{0,0,1.2}}],
	Line[{{0,0,0},{0,1.2,0}}],
		{Thickness[.01],Line[{{1,0,0},{1+.7,0,0}}],
	Line[{{1+.7,0,0},{1+.7, Cos[7],0}}]},
	Text["P",{1,-.05,0}],
	Text["Q",{.8,-.05,Sqrt[1 - .8^2]}],
	Text["R",{.72,.05,0}],
	Text["S",{.75,.82,.6}],
	Text["T",{.75,.82,0}],
	Text["U",{1.09,.82,0}],
	Text["V",{1.8,.04,0}],
	Text["O",{-.02,.03,.03}],
	Text["N",{1.65,Cos[.7],.03}],
	Text["M",{.97,1.02,.03}],
	Text["(x,f(x))",{1.80,Cos[.7] + .08,0}],
	Text["a",{.25,0,.11}],
	Text["B",{0,.03,1.02}],
	Text["C",{1 + Pi/2+.02,.03,0}],
	Text["w",{.9,.025,0}],
	Text["w",{.9,.78,0}],
	Text["w",{1.05,.90,0}]}],	
	PlotRange->{{0,3},{0,1},{0,1}},
	AspectRatio->Automatic]

Input := 

solutionPlot = Show[p0,p1,p2,p3]