若等差数列a1,a2,a3,...,an,...的公差为d,则数列a1,a4,a7,...,a3n-2,...公差为
若等差数列a1,a2,a3,...,an,...的公差为d,则数列a1,a4,a7,...,a3n-2,...公差为
等差数列{an}的公差为d,则数列a1+a4,a2+a5,a3+a6,.是什么数列
等差数列an的公差为d=2,若a1,a3,a4成等比数列,求a2.
等差数列{An}的公差为D,若a1,a2,a3,a4,a5,a6,a7,的方差为1,则D=
设递增等差数列{an}的公差为d,若a1,a2,a3,a4,a5,a6,a7的方差为1,则d=______.
设等差数列{an}公差为d,若a1,a2,a3,a4,a5,a6,a7的方差为1,则d=?
已知等差数列(an)的公差为2,若a1,a3,a4成等比则a2=?
已知等差数列{an}的公差为2,若a1,a3,a4成等比数列,则a2=?
设等差数列{an}的公差为d,则"a1,a2,a3,a4,a5,a6,a7的方差为1"的充要不得条件是d=
已知等差数列{an}的公差为2,若a1,a3,a4成等比数列,则a2+a3的值为( )
已知等差数列{an}的公差为3,若a1,a3,a4成等比数列,则a2=
等差数列an ,的公差为3,若a1,a3,a4成等比数列,则a2=?