1.集合M={x|x=sinnπ3,n∈Z},N={x|x=cosnπ2,n∈N},则M∩N等于 ( )
A.{-1,0,1} B.{0,1} C.{0} D.∅
解析:∵M={x|x=sinnπ3,n∈Z}={-32,0,32},
N={-1,0,1},
∴M∩N={0}.
答案:C
2.已知α∈(π2,π),sinα=35,则tan(α+π4)等于 ( )
A.17 B.7 C.-17 D.-7
解析:由α∈(π2,π),sinα=35,得tanα=-34,tan(α+π4)=1+tanα1-tanα=17.
答案:A
3.若函数f(x)=(1+3tanx)cosx,0≤x<π2,则f(x)的最大值为 ( )
A.1 B.2 C.3+1 D.3+2