please help me solve this question and show all your work please (That includes being very clear about your change(s) of variables.). thank you very much

2 Consider the domain D contained in the rst quadrant and bound by the ellipse % + 29 = 1 . Use an appropriate change of variable (maybe two changes of variables) to help you evaluate: 3:2 $02 ffD cos( + E)dA Make sure to write a clear, complete, and detailed solution. That includes being very clear about your change(s) of variables