How do I write an expression like this question in matlab codes and execute it without errors but logical answers?

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Using double integral.Find the volume of the solid lying under the elliptic paraboloid x2/4+y2/9+ z = 1 and above the rectangle R = [−1,1]×[−2,2]
  6 Comments
Eneriko Ratuloaloa
Eneriko Ratuloaloa on 5 Oct 2018
with(plots); f := (x,y) ->1-x^2/4-y^2/9: a := -1: b := 1: c := -2: d := 2: pic1 := plot3d(f(x,y), x = a ..b, y = c..d, color=red, style=patch): pic2 := plot3d( [x, c, f(x,c)*u], x = a..b, u = 0..1, color=yellow): pic3 := plot3d( [x, d, f(x,d)*u], x = a..b, u = 0..1, color=yellow): pic4 := plot3d( [a, y, f(a,y)*u], y = c..d, u = 0..1, color=yellow): pic5 := plot3d( [b, y, f(b,y)*u], y = c..d, u = 0..1, color=yellow):
display3d({pic1, pic2,pic3, pic4,pic5}, axes=framed; orientation = [45,80]; title = `f := (x,y) ->1-x^2/4-y^2/9`, titlefont = [HELVETICA, BOLD, 10]); int( int( f(x,y), x=-1..1), y=-2..2); 166/27;
if true
% code
end

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Accepted Answer

Dimitris Kalogiros
Dimitris Kalogiros on 5 Oct 2018
Edited: Dimitris Kalogiros on 5 Oct 2018
Try the following script
close all
clearvars
syms x y z
z=-(x^2)/4 - (y^2)/9 +1
fsurf(z);
xlabel('x'); ylabel('y'); zlabel('z');
vol= int( int(z, x, -1, 1 ) , y, -2, 2)
If you run it, it would give something like this:

More Answers (1)

satish
satish on 13 Jan 2023
find the volume of the solid S that is bounded by the elliptic paraboloid x^2+2*y^2+z-16=0, the planes x=2 and y=2 and the three coordinate planes.
  1 Comment
Walter Roberson
Walter Roberson on 13 Jan 2023
please expand on the mathematics to demonstrate that this volume is the same as the volume that the original poster was asking about. The identity of those two volumes is not obvious to me, so I do not understand how this is a solution to the question asked.

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