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数学
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证明:1+cos^2a/sin^2a=1/sin^2a
RT
人气:353 ℃ 时间:2020-04-26 21:07:27
解答
1+cos^2a/sin^2a=sin^2a/sin^2a+cos^2a/sin^2a
=(sin^2a+cos^2a)/sin^2a
=1/sin^2a.
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