已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α=-根号2COS(x+b),且α,b属于(0,π),求α,b已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α)=-根号2COS(π+b),且α,b属于(0,π),求α,b
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![已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α=-根号2COS(x+b),且α,b属于(0,π),求α,b已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α)=-根号2COS(π+b),且α,b属于(0,π),求α,b](/uploads/image/z/535635-27-5.jpg?t=%E5%B7%B2%E7%9F%A5SIN%283%CF%80-%CE%B1%29%3D%E6%A0%B9%E5%8F%B72COS%283%2F2%CF%80%2Bb%29%2C%E6%A0%B9%E5%8F%B73COS%28-%CE%B1%3D-%E6%A0%B9%E5%8F%B72COS%EF%BC%88x%2Bb%EF%BC%89%2C%E4%B8%94%CE%B1%2Cb%E5%B1%9E%E4%BA%8E%EF%BC%880%2C%CF%80%EF%BC%89%2C%E6%B1%82%CE%B1%2Cb%E5%B7%B2%E7%9F%A5SIN%283%CF%80-%CE%B1%29%3D%E6%A0%B9%E5%8F%B72COS%283%2F2%CF%80%2Bb%29%2C%E6%A0%B9%E5%8F%B73COS%28-%CE%B1%29%3D-%E6%A0%B9%E5%8F%B72COS%EF%BC%88%CF%80%2Bb%EF%BC%89%2C%E4%B8%94%CE%B1%2Cb%E5%B1%9E%E4%BA%8E%EF%BC%880%2C%CF%80%EF%BC%89%2C%E6%B1%82%CE%B1%2Cb)
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已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α=-根号2COS(x+b),且α,b属于(0,π),求α,b已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α)=-根号2COS(π+b),且α,b属于(0,π),求α,b
已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α=-根号2COS(x+b),且α,b属于(0,π),求α,b
已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α)=-根号2COS(π+b),且α,b属于(0,π),求α,b
已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α=-根号2COS(x+b),且α,b属于(0,π),求α,b已知SIN(3π-α)=根号2COS(3/2π+b),根号3COS(-α)=-根号2COS(π+b),且α,b属于(0,π),求α,b
平方法(详见参考资料)
sin(3π-α)=√2cos(3/2π+β),
sinα=√2sinβ,①
√3cos(-α)=-√2cos(π+β),
√3cosα=√2cosβ,②
①^2+②^2
sin^2α+3cos^2α=2,
解得sinα=±√2/2,
又α,β∈(0,π),
∴sinα=√2/2.代入①,sinβ=1/2.,
由②知,cosα与cosβ同号.
∴α1=π/4,β1=π/6;
α2=3π/4,β2=5π/6.
温馨提示:请您参阅参考资料
http://hi.baidu.com/ok%B0%C9/blog/item/2aef69e6f25b1629b93820f2.html