Hello.
First time here for me.
I want to plot the vector field A, 
over the region 
I tried the following:
VectorPlot[{y, -x}, {x, y} \[Element] (1/4 < x^2 + y^2 && x^2 + y^2 < 9)]
But it doesn't work, although
RegionPlot[1/4 < x^2 + y^2 && x^2 + y^2 < 9, {x, -4, 4}, {y, -4, 4}]
does return the correct region.
Can someone give me any kind of help with it? Or explain where is the syntax error?
