P(-5,2) - II ćwiartka
[tex]P(-5,2) \ \ \rightarrow \ \ x = -5, \ \ y = 2\\\\r^{2} = x^{2}+y^{2}\\\\r^{2} = (-5)^{2}+2^{2}\\\\r^{2} = 25+4\\\\r^{2} = 29\\\\r = \sqrt{29}[/tex]
[tex]sin\alpha = \frac{y}{r}\\\\sin\alpha = \frac{2}{\sqrt{29}}\cdot\frac{\sqrt{29}}{\sqrt{29}} = \frac{2\sqrt{29}}{29}\\\\\\cos\alpha = \frac{x}{r}\\\\cos\alpha = \frac{-5}{\sqrt{29}}=\frac{-5}{\sqrt{29}}\cdot\frac{\sqrt{29}}{\sqrt{29}} = -\frac{5\sqrt{29}}{29}\\\\\\tg\alpha = \frac{y}{x}\\\\tg\alpha = \frac{2}{-5} = -\frac{2}{5}\\\\\\ctg\alpha = \frac{x}{y}\\\\ctg\alpha = \frac{-5}{2} = -\frac{5}{2}[/tex]
