Giá trị lượng giá một số góc đặc biệt:
$\begin{array}{|l|r|} \hline \quad\alpha & 0\,&\dfrac{\pi}{6}\,&\dfrac{\pi}{4}\,&\dfrac{\pi}{3}\,&\dfrac{\pi}{2}\,&\dfrac{2\pi}{3}\,\,&\dfrac{3\pi}{4}\,\,&\dfrac{5\pi}{6}\,\,&\pi\,\,\,\,&\dfrac{3\pi}{2}&2\pi\,\,\,\\ &\overline{0^o}&\overline{30^o}&\overline{45^o}&\overline{60^o}&\overline{90^o}&\overline{120^o}\,&\overline{135^o}\,&\overline{150^o}\,&\overline{180^o}&\overline{270^o}&\overline{360^o}\\ \hline \sin\alpha &0&\dfrac{1}{2}\,&\dfrac{\sqrt2}{2}&\dfrac{\sqrt3}{2}&1\,\,\,&\dfrac{\sqrt3}{2}&\dfrac{\sqrt2}{2}&\dfrac{1}{2}&0\,\,\,\,&-1\,\,&0\,\,\,\,\,\\ \hline \cos\alpha&1&\dfrac{\sqrt3}{2}&\dfrac{\sqrt2}{2}&\dfrac{1}{2}&0\,\,&-\dfrac{1}{2}&-\dfrac{\sqrt2}{2}&-\dfrac{\sqrt3}{2}&-1\,\,&0\,\,\,&1\,\,\,\,\\ \hline \tan\alpha&0&\dfrac{\sqrt3}{3}&1\,\,&\sqrt3\,\,&||\,\,&-\sqrt3&-1\,\,\,&-\dfrac{\sqrt3}{3}&0\,\,\,&||\,\,\,&0\,\,\,\\ \hline \cot\alpha&||&\sqrt3&1\,\,&\dfrac{\sqrt3}{3}&0\,\,&-\dfrac{\sqrt3}{3}&-1\,\,&-\sqrt3&||\,\,&0\,\,&||\,\,\\ \hline \end{array}$
