Let $\displaystyle W$ be the lamina in the plane enclosed by the curve $\displaystyle xy = 1$ and by the lines $\displaystyle y = (1/3) x$;$\displaystyle y = 5x$, i. e. ,

$\displaystyle W := [(x; y) |$ $\displaystyle (1/3) x$$\displaystyle \le$ y $\displaystyle \le$$\displaystyle 5x$; $\displaystyle x$ $\displaystyle \ge$ $\displaystyle 0$; $\displaystyle xy \le 1$ ].

Given that the density p(x; y) of the lamina is given by $\displaystyle p(x; y) = x^2 + y^2$ , calculate the mass of the

lamina.

the substitution u$\displaystyle = xy; v = y/x$could be used or otherwise.