如图,在四边形ABCD中,AB=AD,对角线AC,BD交于点E,点O在线段AE上,⊙O过B,D两点,若OC=5,OB=3,且cos∠BOE=.求证:CB是⊙O的切线.
计算: (1)(+45)+(-92)+5+(-8) (2) (3)÷ (4)+︱6-10︱-
计算: (2+1)(22+1)(24+1)=(2-1)(2+1)(22+1)(24+1)=(22-1)(22+1)(24+1)=(24-1)(24+1)=(28-1). 根据上式的计算方法,请计算(3+1)(32+1)(34+1)…(332+1)-的值.
计算 (1) (2)
计算:.
(本题6分)计算: