# How to draw bounding surfaces with Plot3D?

Posted 8 years ago
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 Hi. I started with Mathematica and have some troubles.I need to figure bounded by a given surfaces:z = 0; z = x; y = 0; y = 4; x = sqrt(25 - y^2)I try to reproduce that in Mathematica, but makes something wrong and don't understand how to make it rightIn documentation I find Plot3D function and try using it. f[x_, y_] := 0; g[x_, y_] := x; h[x_] := 0; m[x_] := 4; b[y_] := sqrt (25 - y^2); Plot3D[{f[x, y], g[x, y], h[x], m[x], b[y]}, {x, 0, 10}, {y, 0, 4}] And getting something like this:My friend gave me this image that he made himself by hand, but I'm not sure how much it is correct, and decided to do the same automatically using Mathematica
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Posted 8 years ago
 In Mathematica, Sqrt[x], not, sqrt(x}. Make sure your syntax is correct and the predicate resolves to True or False only.
Posted 8 years ago
 You could use RegionPlot3D, but your curves do not appear to bound an enclosed volume.
Posted 8 years ago
 Thank you, but RegionPlot3D working with predicates. Try it but nothing RegionPlot3D[ y >= 0 && y <= 4 && x >= 0 && x <= sqrt (25 - y^2) && z >= 0 && z <= x , {x, -10, 10}, {y, -10, 10}, {z, -10, 10} ]