本题用极坐标
∫∫x²ydxdy
=∫∫ r²(cosθ)² rsinθ r drdθ
=∫[0-->π/2] (cosθ)²sinθdθ ∫[0-->1]r^4dr
=-∫[0-->π/2] (cosθ)²d(cosθ)*1/5r^5 [0-->1]
=-1/5*1/3(cosθ)³ [0-->π/2]
=1/15
本题用极坐标
∫∫x²ydxdy
=∫∫ r²(cosθ)² rsinθ r drdθ
=∫[0-->π/2] (cosθ)²sinθdθ ∫[0-->1]r^4dr
=-∫[0-->π/2] (cosθ)²d(cosθ)*1/5r^5 [0-->1]
=-1/5*1/3(cosθ)³ [0-->π/2]
=1/15