已知(1+tanA)/(1-tanA)=3+2倍根号2,求[(sinA+cosA)^2]-(cosA^3/sinA)
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(1+tanA/(1-tanA)=3+2根号2.
1+tanA=3+2根号2-(3+2根号2)tanA
(4+2根号2)tanA=2+2根号2
tanA=根号2/2
[(sinA+cosA)^2-1]/(cotA-sinAcosA)
=(1+2sinAcosA-1)/(cotA-sinAcosA)
=2sinAcosA/(cosA/sinA-sinAcosA)
=2sinA/(1/sinA-sinA)
=2(sinA)^2/[1-(sinA)^2]
=2(sinA)^2/(cosA)^2
=2(tanA)^2
=2*1/2
=1======以下答案可供参考======
供参考答案1:
tanA=1+根号2/2+根号2