+647 The figure below shows the ellipse \(\frac{(x-20)^2}{20}+\frac{(y-16)^2}{16}=2016\).
Let R1, R2, R3 and R4 denote those areas within the ellipse that are in the first, second, third, and fourth quadrants, respectively. Determine the value of R_1-R_2+R_3-R_4 .
