tan(3x)

tan(3x)證明

3tanx-tan^3x
------------------ = tan3X
1-3tan^2x

這是證明題
tan2x+tanx
---------------------- <=Tan (2x+x) <= Tan3x
1-(tan2x)(tanx)


Tan^3X = 3 power of Tanx <=== 忘了中文怎講 抱歉..

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