sinx=2-3cosx.sinx^2=1-cosx^2=(2-3cosx)^2.得到10cosx^2-12cosx+3=0
得到cosx=(6+-根号6)/10
原是=(2-4cosx)/(2-2cosx)=2-1/(1-cosx)=2-10/(4-+根号6)=2-(4+-根号6)=+-根号6-2原式后面的步骤能在具体点么?看不懂... 谢谢!~就是把sinx=2-3cosx带入原是得到(2-4cosx)/(2-2cosx)。。约分的(1-2cosx)/(1-cosx),,,分子=2-2cosx+-1所以除以分母=2-1/(1-cosx)带入cosx=(6+-根号6)/10之后分母有理化就行了,,
已知sinx+3cosx=2,求(sinx-cosx)/(sinx+cosx)的值
已知sinx+3cosx=2,求(sinx-cosx)/(sinx+cosx)的值
数学人气:354 ℃时间:2020-01-31 05:06:32
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