Calculating the Total Mass on a Surface Bounded by a Triangle

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Homework Help Overview

The problem involves calculating the total mass of a surface defined by a plane equation above a triangular region in the xy-plane. The density function is given in terms of x, y, and z.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of double integrals to find the total mass and explore the limits of integration. There is a suggestion to convert to polar coordinates, which is questioned by another participant who advises against it.

Discussion Status

The discussion includes attempts to set up the integral correctly, with one participant expressing confusion about the limits in polar coordinates. Another participant suggests a simpler approach by expressing z in terms of x and y. The conversation indicates progress towards clarification without reaching a consensus.

Contextual Notes

There is mention of a potential mistake in the integral setup, specifically regarding the notation for differentials. The original poster also notes a delay in their response, indicating ongoing engagement with the problem.

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Homework Statement


Let the surface S be the part of the plane 2x-y+z=3 that lies above the triangle in the xy plane that is bounded by the lines y=0, x=1 and y=x. Find the total mass of S if its density (mass per unit area) is given by

ρ(x,y,z)= xy+z


Homework Equations





The Attempt at a Solution



Ok so i know this is a double integral. the limite will be
0≤x≤1
0≤y≤2x-3

and f'(x)= 2, f'(y)= -1

√(f'(x) + f'(y) + 1)= √6

so my equation is

√6∫∫(xy+z)

and i have a feeling I am meant to convert this into polar coordinates but how do you convert the limits to polar coordinates?
 
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You don't need any polar coordinates here. You simply need to express z via x and y in the integral you have got so far. And by the way, it is a mistake not to write dxdy in the integral.
 
A volume integral seems to yield an easy result here.
 
thanks heaps guys, i figured it out, and sorry about the late reply
 

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