【简答题】已知sin 2 β-2sinα+1=0,α,β∈R,则sin 2 α+sin 2 β的取值范围是______.
【简答题】已知sinαcosβ= 1 2 ,则cosαsinβ的取值范围是______.
【简答题】已知sin 2 β﹣2sinα+1=0,α,β∈R,则sin 2 α+sin 2 β的取值范围是 _________ .
【单选题】What is the main idea of the passage?
A.
American firms' human resource management strategies affect their competitive capacity.
B.
Human resource management is a key factor in a fu-m's survival.
C.
The cost of work training in America is higher than that in Japan and Germany.
D.
American firms are different from Japanese and German firms in human resource management.
【单选题】已知角 α 是钝角, β 角锐角,则 α-β 的范围是( ) A 、(-π,0) B 、( , ) C 、(π, ) D 、(0,π)
【简答题】到2020年全面建设小康社会目标实现之时,我国将成为( )。