\sin\alpha = \frac{2}{3}
\alpha należy do (0,\pi)
\sin^2\alpha+\cos^2\alpha=1
(\frac{2}{3})^2+\cos^2\alpha=1
\frac{4}{9}+\cos^2\alpha=1
\cos^2\alpha=1-\frac{4}{9}
\cos^2\alpha=\frac{5}{9}
cos\alpha=\sqrt{\frac{5}{9}}=\frac{\sqrt{5}}{3}\approx0,74536
lub
cos\alpha=-\sqrt{\frac{5}{9}}=-\frac{\sqrt{5}}{3}\approx-0,7454
\tan\alpha=\frac{\sin\alpha}{\cos\alpha}
\sin\alpha=\frac{2}{3}=0,6667
\tan\alpha=\frac{0,6667}{0,7454}=0,8944
lub
\tan\alpha=\frac{0,6667}{-0,7454}=-0,8944
\cot\alpha=\frac{1}{\tan\alpha}=\frac{1}{0,8944}=1,1180
lub
\cot\alpha=\frac{1}{\tan\alpha}=\frac{1}{-0,8944}=-1,1180