Question

find the area under the curve.. http://puu.sh/2v8Mb
what do x and y mean in the equations.. anyone know?

Answer 1

you are given the parametric equations for the curve
\[x=\cos\phi\implies dx=-\sin\phi\,d\phi\\
y=4\sin\phi\implies dy=4\cos\phi\,d\phi\]

Answer 2

why x and y, why not r?

Answer 3

this is an ellipse with the patametric form
\[x=a\cos\phi\\y=b\sin\phi\]

Answer 4

follow?

Answer 5

this is not "polar co-ordinate" representation.
phi is just a parameter

Answer 6

aights