k=(2sin^2a+sin2a)/(1+tana) 则sin(a-3.14/4)的值
人气：133 ℃ 时间：2020-03-30 01:02:06
解答
k=(2sin^2a+sin2a)/(1+tana)
＝2sinacosa(sina+cosa)/(cosa+sina)
=2sinacosa=sin2x≤1
1-k=1-2sinacosa
sina-cosa=±√(1-k)
sin(a-∏/4)
=√2/2(sina-cosa)
==±√[2(1-k)]/2
推荐
- Tana=2 ,sin^2a+sin2a\cos^2a+2sin^2a的值为?
- 证明(sin2A+sin^2A)/（2cos2A+2sin^2A+cosA ）=tanA
- 已知tana=2,求sin^2+sin2a/cos^2a+cos2a和2sin^2a+sinacosa
- 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.
- sin(π/4+2a)sin(π/4-a)=1/4,a∈(π/4,π/2),求2sin方a+tana-1/tana-1的值?
- 英式音标里的前元音,后元音,中元音分别是哪些
- The girl couldn't say a word because she was s_____
- 用纸上谈兵、揭竿而起、破釜沉舟、项庄舞剑,意在沛公、四面楚歌写篇小短文.
猜你喜欢
