等比数列中,若,,,成等差数列,则______.
己知等差数列的公差不为零,其前n项和,若成等比数列,则________.
设为公比的等比数列的前项和,且,,成等差数列,则__________,________.
已知数列是等比数列,,则__________.
已知数列是等差数列,,且,,成等比数列,则______.
等比数列的前三项和,若,,成等差数列,则公比______.