Question

高一数学求过程

高一数学求过程急急急11.12题过程

Answer 1

11.
0<θ<π/4，0<sinθ<cosθ，sinθ-cosθ<0
(sinθ+cosθ)²=1+2sinθcosθ=16/9
2sinθcosθ=7/9
(sinθ-cosθ)²=1-2sinθcosθ=1-7/9=2/9
sinθ-cosθ=-√2/3
选B
12.
f(2009)=asin(2009π+α)+bcos(2009π+β)
=-asinα-bcosβ
=5
f(2016)=asin(2016π+α)+bcos(2016π+β)
=asinα+bcosβ
=-(-asinα-bcosβ)
=-5
选C