已知sinA+3cosA=2,求(sinA-cosA)/(sinA+cosA)的值已知sina+3cosa=2,求(sina-cosa)/(sina+cosa) 令(sina-cosa)/(sina+cosa) =t即(t-1)sina+(1+t)cosa=0_______________________该式又sina+3cos=2综上得到:sina=(1+t)/(2-t),cosa=(t-1
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![已知sinA+3cosA=2,求(sinA-cosA)/(sinA+cosA)的值已知sina+3cosa=2,求(sina-cosa)/(sina+cosa) 令(sina-cosa)/(sina+cosa) =t即(t-1)sina+(1+t)cosa=0_______________________该式又sina+3cos=2综上得到:sina=(1+t)/(2-t),cosa=(t-1](/uploads/image/z/6865696-64-6.jpg?t=%E5%B7%B2%E7%9F%A5sinA%2B3cosA%3D2%2C%E6%B1%82%28sinA-cosA%29%2F%28sinA%2BcosA%29%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5sina%2B3cosa%3D2%2C%E6%B1%82%28sina-cosa%29%2F%28sina%2Bcosa%29+%E4%BB%A4%28sina-cosa%29%2F%28sina%2Bcosa%29+%3Dt%E5%8D%B3%EF%BC%88t-1%29sina%2B%EF%BC%881%2Bt%EF%BC%89cosa%3D0_______________________%E8%AF%A5%E5%BC%8F%E5%8F%88sina%2B3cos%3D2%E7%BB%BC%E4%B8%8A%E5%BE%97%E5%88%B0%EF%BC%9Asina%3D%EF%BC%881%2Bt%EF%BC%89%2F%EF%BC%882-t%EF%BC%89%2Ccosa%3D%EF%BC%88t-1)
已知sinA+3cosA=2,求(sinA-cosA)/(sinA+cosA)的值已知sina+3cosa=2,求(sina-cosa)/(sina+cosa) 令(sina-cosa)/(sina+cosa) =t即(t-1)sina+(1+t)cosa=0_______________________该式又sina+3cos=2综上得到:sina=(1+t)/(2-t),cosa=(t-1
已知sinA+3cosA=2,求(sinA-cosA)/(sinA+cosA)的值
已知sina+3cosa=2,求(sina-cosa)/(sina+cosa)
令(sina-cosa)/(sina+cosa) =t
即(t-1)sina+(1+t)cosa=0_______________________该式
又sina+3cos=2
综上得到:sina=(1+t)/(2-t),cosa=(t-1)/(t-2)___________该式
不知道以上三式是如何得到的,
已知sinA+3cosA=2,求(sinA-cosA)/(sinA+cosA)的值已知sina+3cosa=2,求(sina-cosa)/(sina+cosa) 令(sina-cosa)/(sina+cosa) =t即(t-1)sina+(1+t)cosa=0_______________________该式又sina+3cos=2综上得到:sina=(1+t)/(2-t),cosa=(t-1
(sina-cosa)/(sina+cosa)=t
sina-cosa=t*sina+t*cosa
(1-t)*sina=(1+t)cosa
所以第一个式子得证
因为sina+3cosa=2
所以sina=2-3cosa
把这个式子带到第一个式子,得到(t-1)*(2-3*cosa)+(1+t)cosa=0
所以2*t-3*t*cosa-2+3*cosa+cosa+t*cosa=0
所以2*cosa-t*cosa=1-t
所以cosa=(t-1)/(t-2)第三个式子得证
把第三个式子带到sina=2-3cosa
得到sina=(1+t)/(2-t)第二个式子得证