Filling Question
\tan \dfrac{\pi}{5}+ \tan \dfrac{2\pi}{5}+\tan \dfrac{3\pi}{5}+\tan \dfrac{4\pi}{5}=
Steven Zheng
posted 3 years ago
Answer
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\tan \dfrac{\pi}{5}+ \tan \dfrac{2\pi}{5}+\tan \dfrac{3\pi}{5}+\tan \dfrac{4\pi}{5}=
=\tan \dfrac{\pi}{5}+\tan \dfrac{2\pi}{5}+\tan (\pi- \dfrac{2\pi}{5}) +\tan (\pi-\dfrac{\pi}{5})
=\tan \dfrac{\pi}{5}+\tan \dfrac{2\pi}{5}-\tan \dfrac{2\pi}{5}-\tan \dfrac{\pi}{5}
=0
Steven Zheng
posted 3 years ago