已知 x,y∈[−π4,π4],a∈R ，且x3+sinx﹣2a=0，4y3+ 12 sin2y+a=0，则cos（x+2y）的值为_刷题宝

题干

已知 x,y∈[−

π

4

,

π

4

],a∈R ，且x³+sinx﹣2a=0，4y³+

1

2

sin2y+a=0，则cos（x+2y）的值为（）

A：0

B： $\frac{1}{4}$

C： $- \frac{1}{2}$

D：1

上一题下一题 0.0难度选择题更新时间:2019-05-18 08:44:35

答案(点此获取答案解析）

D

同类题1

人体的运动由运动系统来完成，运动系统的功能是（）

同类题2

想一想，下面的字母分别代表几？

A＝____B＝____C＝____

同类题3

— Excuse me, sir. Please don't take photos in the museum. Look at the sign .

— I'm sorry. I didn't notice it just now.

同类题4

不共线，对于空间任意一点

同类题5

用所给词的适当形式填空

①To make a sandwich, we need two ____ (slice) of bread, some vegetables and some meat.

② It rained hard yesterday, but ____ (luck) we brought our raincoats and didn't get wet.

③Ted told us an unusual story ____ (call) Mystery steps.

④ Cindy had fun ____ (make) flashcards with her cousin.

⑤ How old was Laura when she became a ____ (skate) champion?

小学学科试题库

初中学科试题库

高中学科试题库