作业帮(1+sin x)/(1-sin x) = (2 sec^2 x )+(2 sec x tanx) - 1 怎么证明出来,只能动(1+sin x)/(1-sin x) ,不能动右边的.
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(1+sin x)/(1-sin x) = (2 sec^2 x )+(2 sec x tanx) - 1 怎么证明出来,只能动(1+sin x)/(1-sin x) ,不能动右边的.
(1+sin x)/(1-sin x) = (2 sec^2 x )+(2 sec x tanx) - 1 怎么证明出来,
只能动(1+sin x)/(1-sin x) ,不能动右边的.
(1+sin x)/(1-sin x) = (2 sec^2 x )+(2 sec x tanx) - 1 怎么证明出来,只能动(1+sin x)/(1-sin x) ,不能动右边的.
(1+sinx)/(1-sinx)
=(1+sinx)^2/(1-sinx)(1+sinx)
=(1+2sinx+sin^2x)/(1-sin^2x)
=(1+2sinx+sin^2x)/cos^2x
=sec^2x+2secxtanx+tan^2x
=2sec^2x+2secxtanx-(sec^2x-tan^2x)
=2sec^2x+2secxtanx-1
(2 sec^2 x )+(2 sec x tanx) - 1
=(2/cos²x)+(2sinx/cos²x)-1
=(2+2sinx-cos²x)/cos²x
=(sin²x+2sinx+1)/(1-sin²x)
=(sinx+1)²/[(1-sinx)(1+sinx)]
=(1+s...
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(2 sec^2 x )+(2 sec x tanx) - 1
=(2/cos²x)+(2sinx/cos²x)-1
=(2+2sinx-cos²x)/cos²x
=(sin²x+2sinx+1)/(1-sin²x)
=(sinx+1)²/[(1-sinx)(1+sinx)]
=(1+sinx)/(1-sinx)
右边=左边
得证
要想只动左边的(1+sin x)/(1-sin x) ，
那你把上面的解法从下往上写，就行了。。
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