>
数学
>
已知cos(a+b)=0,求值:sin(π+2a+b)-cos(-π/2+2a+3b)
人气:283 ℃ 时间:2020-06-20 09:30:40
解答
原式=-sin(2a+b)-sin(2a+3b)
sin(2a+b)=sin(2a+2b-b)=sin2(a+b)cosb-cos2(a+b)sinb
sin(2a+3b)=sin(2a+2b+b)=sin2(a+b)cosb+cos2(a+b)sinb
cos(a+b)=0,sin2(a+b)=2sin(a+b)cos(a+b)=0
原式=cos2(a+b)sinb-cos2(a+b)sinb=0
推荐
求值sin^2A+cos^2(A+30°)+sinAcos(A+30°)
2a*cosθ+√3b*sinθ≤√(4a^2+3b^2) 怎么推出的
已知sin(π6−a)=13,则cos(2π3+2a)的值是( ) A.-79 B.-13 C.13 D.79
sin^a+cos^(π/6+a)+1/2sin(2a+π/6)求值
已知sin(π/3-a)=1/3,则cos(2π/3-2a)=( )
0.02mm游标卡尺
怎么利用音标来背单词?
用排水法收集气体是,需用什么仪器?
猜你喜欢
Could you buy some apples for the party?There are_______ apples at home.A.many B.much C.little D.few
警车、消防车、救护车笛声有什么不同
等差数列,a6+a7+a8=60,a3+a11=?
悯农的锄禾日当午
The flood has done _____ to this area.A.damages B.many damages C.much damage D.damaging
电场强度:E=F/Q
左边一个鱼字,右边一个儿字的繁体读什么字?
6元等于()元 ()里填两位小数
© 2024 79432.Com All Rights Reserved.
电脑版
|
手机版