{ r = 1 + cosθ{ r = 1交点(r,θ)为[1,π/2]和[- 1,- π/2]面积 = 2∫[0→π/2] (1/2)(1)² dθ + 2∫[π/2→π] (1/2)(1 + cosθ)² dθ= [π/2] + [3π/4 - 2]= 5π/4 - 2= (5π - 8)/4