题目

已知点M的直角坐标为(1,-3,4),则它的柱坐标为_______. 答案：解析:设点M的柱坐标为(ρ,θ,z),则,解之,得ρ=2,θ=,z=4.∴点M的柱坐标为(2,,4).答案:(2,,4).Between the two parts of the concert is an interval, ______ the audience can buy ice-cream.A．whenB．whereC．that D．which