I am really sorry to bother you for the same problems, but I cannot get in the view about this command, the filling option.
What I want: to fill the semicircle part, under the $y = x$ curve. Here is what I did so far, but there is a slight piece filled in excess. Can you please tell me how I would proceed?
f[x_] = 1 + Sqrt[1 - (x - 1)^2];
h[x_] = x;
g[x_] = 1 - Sqrt[1 - (x - 1)^2];
Plot[{f[x], g[x], h[x],
ConditionalExpression[h[x], 0 < x < 2]}, {x, -1, 3},
AspectRatio -> Automatic,
PlotStyle -> {{Darker@Cyan, Dashed}, {Darker@Cyan,
Dashed}, {Darker@Green, Dashed}, Darker@Green},
Filling -> {3 -> {2}}, FillingStyle -> {None, LightRed},
PlotRange -> {-1.5, 2.5}, AxesStyle -> Arrowheads[{0.05}],
GridLines -> {{{-2, {Thick, AbsoluteDashing[{3, 3}]}}}, None},
Epilog -> {{AbsoluteThickness[1.75]}, AbsoluteDashing[3, 3],
Line[{{1 + 1/Sqrt[2], 0}, {1 + 1/Sqrt[2], 1 + 1/Sqrt[2]}}],
Line[{{1 + 1/Sqrt[2], 1 + 1/Sqrt[2]}, {0, 1 + 1/Sqrt[2]}}]}]