(本题6分)计算:
(本题6分) (1)已知:sinα·cos60º=,求锐角α; (2)计算:.
(1)(配方法) (2) (3)(4)()()—
计算:.
(每小题5分,本题共20分)计算: (1)(2)(-+-)×(-48) (3)(4)
(本题6分) (1)已知:sinα·cos60°=,求锐角α. (2)计算:.