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[函数] 一眼看尽同角三角求值

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isee Posted 2021-8-6 20:49 |Read mode

（源自 youtube 的 SyberMath 的视频）

若`3\sin x-4\cos x=2`，则`\tan x=`_________.

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kuing Posted 2021-8-6 20:59

齐次化呗

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Author| isee Posted 2021-8-8 00:15

回复 2# kuing

最快的方式：平方，就可以化为齐二次，最后结果`\frac{12\pm2\sqrt{21}}{5}`

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