Question

已知圆的极坐标方程为p=cosθ-sinθ,则该圆的面积为

Answer 1

p=cosθ-sinθ => p^2=pcosθ-psinθ => x^2+y^2=x-y =>(x-1/2)^2+(y+1/2)^2=1/2

r^2=1/2

该圆的面积为π/2