Ω:{(x,y,z)|-c≤z≤c,x²/a²+y²/b²≤1-z²/c²}
原式=∫(-c→c)z²dz∫∫(Dz)dxdy
Dz={(x,y)|x²/a²+y²/b²≤1-z²/c²}
∴∫∫(Dz)dxdy
=π√[a²(1-z²/c²)]√[b²(1-z²/c²)]
=πab(1-z²/c²)
原式=∫(-c→c)πab(1-z²/c²)z²dz
=(4/15)πabc³
不懂继续追问,
Ω:{(x,y,z)|-c≤z≤c,x²/a²+y²/b²≤1-z²/c²}
原式=∫(-c→c)z²dz∫∫(Dz)dxdy
Dz={(x,y)|x²/a²+y²/b²≤1-z²/c²}
∴∫∫(Dz)dxdy
=π√[a²(1-z²/c²)]√[b²(1-z²/c²)]
=πab(1-z²/c²)
原式=∫(-c→c)πab(1-z²/c²)z²dz
=(4/15)πabc³
不懂继续追问,