cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/13 09:50:24
![cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?](/uploads/image/z/3710246-14-6.jpg?t=cos%28%CF%80-%CE%B8%29tan%283%CF%80%2B%CE%B8%29%2Fsin%28%CF%80%2F2%2B%CE%B8%29%3D3%2F4%2C%E5%88%99cos%CE%B8%3D%3F)
x)K/8ߠ{nfIbm S83(o< TynMR>lhkX.X#HC`r`A8r{'dǮkm:stMMU>=JB<;m~OGɚ?"<ӻ# V6~lӟXɧ^l;P)*4U=[qC
cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?
cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?
cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?
cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4
(-cosθ)tanθ/cosθ=3/4
-tanθ=3/4
tanθ=-3/4
当θ为第二象限角时,cosθ=-4/5
当θ为第四象限角时,cosθ=4/5
cos(π-θ)tan(3π+θ)/sin(π/2+θ)=3/4,则cosθ=?
(-cosθtanθ)/(cosθ)=-tanθ=3/4,即tanθ=-3/4,故cosθ=±4/5;
当θ是第二象限角时取负号;当θ是第四象限角时取正号。