来自姜恩华的问题
S=(cos^2x+cos^4x+.+cos^2nx)+(sin^2x+sin^4x+.+sin^2nx)数列求和题!答案是(cos^4x+sin^4x-cos^2n+4x-sin^2n+4x)/sin^2x.cos^2x
S=(cos^2x+cos^4x+.+cos^2nx)+(sin^2x+sin^4x+.+sin^2nx)数列求和题!
答案是(cos^4x+sin^4x-cos^2n+4x-sin^2n+4x)/sin^2x.cos^2x
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2020-11-17 23:21