衡量测量精度的指标有中误差、极限误差和()。
参考答案:相对误差
—Is it all right if I keep this photo?
—________.
A. No, you don't
B. No, it shouldn't
C. I'm afraid not
D. Don't keep it
等比数列{an}同时满足下 * * 个条件:①a1+a6=33;②a2a5=32;③三个数2a2,a32,3a4+4依次成等差数列.求数列{an}的通项公式及前n项和Sn.