已知sin(2a+b)=3sinb 设tana=x tanb=y 记y=f(x) 求f(x)的表达式~跪谢求出f(x)后,求f(2^x)的值域
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![已知sin(2a+b)=3sinb 设tana=x tanb=y 记y=f(x) 求f(x)的表达式~跪谢求出f(x)后,求f(2^x)的值域](/uploads/image/z/3711504-48-4.jpg?t=%E5%B7%B2%E7%9F%A5sin%282a%2Bb%29%3D3sinb+%E8%AE%BEtana%3Dx+tanb%3Dy+%E8%AE%B0y%3Df%28x%29+%E6%B1%82f%28x%29%E7%9A%84%E8%A1%A8%E8%BE%BE%E5%BC%8F%7E%E8%B7%AA%E8%B0%A2%E6%B1%82%E5%87%BAf%28x%29%E5%90%8E%EF%BC%8C%E6%B1%82f%282%5Ex%29%E7%9A%84%E5%80%BC%E5%9F%9F)
已知sin(2a+b)=3sinb 设tana=x tanb=y 记y=f(x) 求f(x)的表达式~跪谢求出f(x)后,求f(2^x)的值域
已知sin(2a+b)=3sinb 设tana=x tanb=y 记y=f(x)
求f(x)的表达式~
跪谢
求出f(x)后,求f(2^x)的值域
已知sin(2a+b)=3sinb 设tana=x tanb=y 记y=f(x) 求f(x)的表达式~跪谢求出f(x)后,求f(2^x)的值域
sin(2a+b)=3sinb
sin[(a+b)+a]=3sin[(a+b)-a]
sin(a+b)cosa+cos(a+b)sina=3[sin(a+b)cosa-cos(a+b)sina]
sin(a+b)+cos(a+b)tga=3[sin(a+b)-cos(a+b)tga]
sin(a+b)+cos(a+b)=3[sin(a+b)-cos(a+b)]
4cos(a+b)=2sin(a+b)
tg(a+b)=2
tg(a+b)=(tga+tgb)/(1-tgatgb)=2
tgb+2tgatgb=2-tga
tgb=(2-tga)/(1+2tga)
y=(2-x)/(1+2x)
sorry
这道题目答案应该是f(x)=x/(1+2x^2)吧
y=(2-x)/(1+2x)
sin(2a+b)=3sinb
sin[(a+b)+a]=3sin[(a+b)-a]
sin(a+b)cosa+cos(a+b)sina=3[sin(a+b)cosa-cos(a+b)sina]
sin(a+b)+cos(a+b)tga=3[sin(a+b)-cos(a+b)tga]
sin(a+b)+cos(a+b)=3[sin(a+b)-cos(a+b)...
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sin(2a+b)=3sinb
sin[(a+b)+a]=3sin[(a+b)-a]
sin(a+b)cosa+cos(a+b)sina=3[sin(a+b)cosa-cos(a+b)sina]
sin(a+b)+cos(a+b)tga=3[sin(a+b)-cos(a+b)tga]
sin(a+b)+cos(a+b)=3[sin(a+b)-cos(a+b)]
4cos(a+b)=2sin(a+b)
tg(a+b)=2
tg(a+b)=(tga+tgb)/(1-tgatgb)=2
tgb+2tgatgb=2-tga
tgb=(2-tga)/(1+2tga)
y=(2-x)/(1+2x) ha~~ha
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