mshd.net
当前位置:首页 >> sin75度sin165度的值是? >>

sin75度sin165度的值是?

原式=sin75sin(180-15) =sin75sin15 =sub75cos(90-15) =sin75cos75 =1/2*(2sin75cos75) =1/2*sin150 =1/4

sin0=0, sin15=(√6-√2)/4 , sin30=1/2, sin45=√2/2, sin60=√3/2, sin75=(√6+√2)/2 , sin90=1, sin105=√2/2*(√3/2+1/2) sin120=√3/2 sin135=√2/2 sin150=1/2 sin165=(√6-√2)/4 sin180=0 sin270=-1 sin360=0

sin165° =sin15° (cos30°=1-2sin²15) =√[(1-cos30°)2] =√[(2-√3)/4] =√[4-2√3)/8] =√[(√3-1)²/8] =(√3-1)/2√2 =√2(√3-1)/4 =(√6-√2)/4 如果你认可我的回答,敬请及时采纳, ~如果你认可我的回答,请及时点击【采纳为满意回答】按钮 ~~...

cos45sin165+sin45sin75 =cos45sin15+sin45cos15 =sin(15+45) =sin60 =√3/2

sin165° =sin15° (cos30°=1-2sin²15) =√[(1-cos30°)2] =√[(2-√3)/4] =√[4-2√3)/8] =√[(√3-1)²/8] =(√3-1)/2√2 =√2(√3-1)/4 (√6-√2)/4

· │ 30 度 │ 45度 │ 60度 sin α │ 二分之一 │ 二分之根号二 │ 二分之根号三 cos α │ 二分之根号三 │ 二分之根号二 │ 二分之一 ☆tan α = sin α ÷ cos α(最好写成分数形式) 即 san α= tan α × cos α sin 15度 = sin (45-30) 即 ☆sin (α-β)书上...

cos105°+ sin165° = cos105°+ cos75° = 2 * cos{(105°+ 75°)/2} * cos{(105°- 75°)/2} = 2 * cos90° * cos15° = 0

sin 15°+cos 165° =sin 15°+cos(180°-15°) =sin15°-cos15° =√2[(√2/2)sin15°-(√2/2)cos15°] =√2sin(15°-45°) =-√2sin30° =-√2/2

cos45*cos15+sin225*sin165 =cos45cos15+sin(180+45)sin(180-15) =cos45cos15-sin45sin15 =cos(45+15) =cos60 =1/2

网站首页 | 网站地图
All rights reserved Powered by www.mshd.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com