已知tana+cota=5/2,求cos2a和sin(2a+π/4)
如题
人气：330 ℃ 时间：2020-02-05 16:36:52
解答
tana+cota=sina/cosa+cosa/sina=[(sina)^2+(cosa)^2]/sinacosa=1/(1/2sin2a)=5/2
sin2a=4/5
cos2a=3/5或-3/5
sin(2a+π/4)=sin2acosπ/4+sinπ/4cos2a=7√2/10或√2/10
推荐
- 帮下 已知sin(π/4+2a) * sin(π/4-2a) =1/4 ,a∈(π/4,π/2,求2sin^a+tana-cota-1的值.
- tana+1/tana=5/2,a∈(π/4,π/2),求cos2a和sin(2a+π/4)?
- 已知sin(4/π+2a)sin(/π4-2a)=1/4,a∈(π/4,π/2),求2(sina)^2+tana-cota-1的值
- 已知sin(pai/4+2a)sin(pai/4-2a)=1/4,a属于(pai/4,pai/2),求2sin^a+tana-cota-1的值
- 若tana+cota=10/3,a∈（π/4,π/2）,则sin(2a+π/4)的值为
- 描写人物外表、动作、神态、心理的成语 各50个
- as as possible的语法和应用!
- my mother was born in 1976.that was the year of________.
猜你喜欢
