设a为锐角,若cos(a+pi/6)=4/5,则sin(2a+pi/12)的值为?
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/06/16 08:49:34
设a为锐角,若cos(a+pi/6)=4/5,则sin(2a+pi/12)的值为?
![设a为锐角,若cos(a+pi/6)=4/5,则sin(2a+pi/12)的值为?](/uploads/image/z/4589264-56-4.jpg?t=%E8%AE%BEa%E4%B8%BA%E9%94%90%E8%A7%92%2C%E8%8B%A5cos%28a%2Bpi%2F6%29%3D4%2F5%2C%E5%88%99sin%282a%2Bpi%2F12%29%E7%9A%84%E5%80%BC%E4%B8%BA%3F)
cos(2a+π/3)=2cos²(a+π/6)-1=7/25
a为锐角,则:2a+π/3∈(π/3,π/2)
∴sin(2a+π/3)=24/25
sin(2a+π/12)=sin[(2a+π/3)-π/4]
=sin(2a+π/3)cosπ/4-cos(2a+π/3)sinπ/4
=(17根号2)/50
a为锐角,则:2a+π/3∈(π/3,π/2)
∴sin(2a+π/3)=24/25
sin(2a+π/12)=sin[(2a+π/3)-π/4]
=sin(2a+π/3)cosπ/4-cos(2a+π/3)sinπ/4
=(17根号2)/50
、设a为锐角,若cos(a+pi/6)=4/5,则sin(2a+pi/12)的值为?
设a为锐角,若cos(a+pi/6)=4/5,则sin(2a+pi/12)的值为?
sin(pi/6-a)=1/3,则cos(2pi/3+2a)的值为
已知a为锐角,且cos(a+pi/4)=3/5,则cosa=
a,b∈(3pi/4,pi),sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos(a+pi/4)=
已知a,b,属于(3pi/4,pi),sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos(a+pi
三角函数:设a为锐角,若cos(a+π/6)=4/5,则sin(2a+π/12)的值为多少?
设a为锐角,若cos(a+π/6)=4/5,则sin(2a+π/12)的值为多少?
设a为锐角,若cos(a+π/6)=4/5,则sin(2a+π/12)的值为?
若cos(pi/6-a)=1/2,sin(a+pi/3)=?cos(2pi/3+2a)=?注:pi指圆周率
化简:sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a)
已知pi/4<a<b<pi/2,且sin(a+b)=4/5,cos(a-b)=12/13,求sina2a的值.