(Ⅰ)求函数f(x)的最小正周期;
(Ⅱ)求函数f(x﹣ )在[0, ]上的最大值与最小值.
(Ⅰ)求证:A1C1⊥AP;
(Ⅱ)求二面角P﹣AM﹣B的余弦值.
(Ⅰ)求an与bn;
(Ⅱ)设数列{cn}满足cn= ,求{cn}的前n项和Tn .