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alias: "tange en fonction de tan(x/2)"
---
up::[[formules de trigonométrie]]
type::$t = \tan\left(\frac{x}{2}\right)$
title::$\tan(x) = \dfrac{2t}{1-t^{2}}$
#s/maths/trigonométrie

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On pose $\disp t = \tan\left(\frac{x}{2}\right)$

$\tan(x) = \dfrac{2t}{1-t^{2}}$