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**Infernorage** Here is the question...

Consider the lamina in the first quadrant of the XY plane bounded by the curve $\displaystyle x^2+y^2=R$. The density of the material is given by $\displaystyle \rho(x,y)=xy$.

a. Use rectangular coordinates to find the mass of this lamina.

b. Use polar coordinates to find the mass of this lamina.

The main thing I don't understand is how to find the limits of the area. I know I need to use $\displaystyle x^2+y^2=R$ and find its limits in the first quadrant, but I don't know what to do with the R. Can someone help me out with this? Thanks.