題目 Problem (O) Evaluate ∭Ωcosx2+y2+z2x2+y2+z2 dxdydz\iiint_\Omega \dfrac{\cos\sqrt{x^2+y^2+z^2}}{x^2+y^2+z^2}\,\mathrm{d}x\mathrm{d}y\mathrm{d}z∭Ωx2+y2+z2cosx2+y2+z2dxdydz, where Ω={(x,y,z):1≤x2+y2+z2≤2}\Omega=\{(x,y,z):1\le x^2+y^2+z^2\le 2\}Ω={(x,y,z):1≤x2+y2+z2≤2}. Answer: (16)‾\underline{\quad(16)\quad}(16). 解答