Calculus 3 change of variables

princessp
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Homework Statement


Use the change of variables to evaluate the integral
(x +y ) sin(x -y )dA, where R is the
region enclosed by y = x, y = x - 2, y = -x and y = -x + 1. (Hint: use u = x + y and
v = x - y

Homework Equations

The Attempt at a Solution


Not sure how to start it
 
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Draw the region in the xy plane and then draw the region in the uv plane to determine bounds. From there, use the standard change of variables...
 
okay i think that's where i am having trouble. I an not good at drawing the graph
 
princessp said:
okay i think that's where i am having trouble. I an not good at drawing the graph

You have to draw the boundary lines. Don't say that you can not draw the lines y = x, y = x - 2, y = -x, and y = -x + 1 !
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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