$(1$ point$)$ Find positive numbers a and $bso$ that the change $of$ variables $s=ax,t=by$ transforms the integral ${}_{R}dxdy$ into

${}_T|\frac{d(x,y)}{d(s,t)}|dsdt$

for the region $R,$ the elliptical region $\frac{x^2}{16}+\frac{y^2}{9}1$ and the region $T,$ the circle $s^2+t^2=1.$

$a=$

$b=$

What $is|\frac{d(x,y)}{d(s,t)}|in$ this case?

$|\frac{\text{d}\text{e}\text{l}(x,y)}{\text{d}\text{e}\text{l}(s,t)}|=$