题目

若cos(α+)=,(0＜α＜),求cosα. 答案：解：∵0＜α＜,∴+α∈(, ).∴sin(α+)==.∴cosα=cos［(α+)-］=cos(α+)cos+sin(α+)sin=·+·=.Fill in the blanks with the right words. 选择适当的词填空. Tom's parents work in ________ (/, the) same university.