Odpowiedź:
[tex]cos\alpha = \frac{2}{3} \\cos^2\alpha = (\frac{2}{3})^2 = \frac{4}{9} \\\\sin^2\alpha + cos^2\alpha = 1\\sin^2\alpha + \frac{4}{9} = 1\\sin^2\alpha = 1-\frac{4}{9} \\sin^2\alpha = \frac{5}{9} \\3sin^\alpha -5 = 3* \frac{5}{9} -5= \frac{5}{3}-5= 1\frac{2}{3}-5=-3\frac{1}{3} \\[/tex]
