已知cos(π/4+x)=3/5,(1π)12
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![已知cos(π/4+x)=3/5,(1π)12](/uploads/image/z/3989061-45-1.jpg?t=%E5%B7%B2%E7%9F%A5cos%28%CF%80%2F4%2Bx%29%3D3%2F5%2C%281%CF%80%2912)
已知cos(π/4+x)=3/5,(1π)12
已知cos(π/4+x)=3/5,(1π)12
已知cos(π/4+x)=3/5,(1π)12
您好:
解答如下
17π/12
cosx=cos(π/4 +x-π/4 )
=cos(π/4 +x)cosπ/4+sin(π/4 +x)sinπ/4
=3/5×√2/2+(-4/5)×√2/2
=-√2/10
因为17π/12
(sin2x+2sin²x)/1-tanx=(7/25+49/25)/(1-7)=-28/75
谢谢采纳,有疑问欢迎您追问