
高等数学,求大神解题,过程越详细越好,谢谢!!! 20
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4. 令 x = rcost, y = rsint,
则 x^2+y^2 = ax 即 r = acost,-π/2 ≤ t ≤ π/2, 0 ≤ r ≤ a
z = x^2+y^2 = r^2
V = ∫∫<D>zdxdy = ∫<-π/2, π/2>dt ∫<0, a> r^2 rdr
= (π/4)[r^4]<0, a> = (π/4)a^4
则 x^2+y^2 = ax 即 r = acost,-π/2 ≤ t ≤ π/2, 0 ≤ r ≤ a
z = x^2+y^2 = r^2
V = ∫∫<D>zdxdy = ∫<-π/2, π/2>dt ∫<0, a> r^2 rdr
= (π/4)[r^4]<0, a> = (π/4)a^4
追问
没写完啊老师
追答
体积求出来了啊
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