计算二重积分∫∫D[y/(1+x2)]dσ,其中D是区域:0≤x≤1;-1≤y≤0.
∫∫D[y/(1+x2)]dσ=∫01dx∫-10[y/(1+x2)]dy =∫01[1/(1+x2)]•[(1/2)y2∣-10]dx =-(1/2)∫01[1/(1+x2)]dx=-(1/2)•arctanx∣01 =-(π/8)
计算二重积分∫∫D[y/(1+x2)]dσ,其中D是区域:0≤x≤1;-1≤y≤0.
∫∫D[y/(1+x2)]dσ=∫01dx∫-10[y/(1+x2)]dy =∫01[1/(1+x2)]•[(1/2)y2∣-10]dx =-(1/2)∫01[1/(1+x2)]dx=-(1/2)•arctanx∣01 =-(π/8)