Odpowiedź:
a - druga przyprostokątna
[tex]a^2=(6,5y)^2-(6y)^2\\a^2=42,25y^2-36y^2\\a^2=6,25y^2\\a=2,5y\\\\cos\alpha=\frac{2,5y}{6,5y}=\frac{5}{13} \\sin\alpha=\frac{6y}{6,5y}=\frac{12}{13} \\\\\frac{3cos\alpha+sin\alpha}{13cos\alpha*sin\alpha} =\frac{3*\frac{5}{13}+\frac{12}{13}}{13*\frac{5}{13}*\frac{12}{13}} =\frac{\frac{15}{13}+\frac{12}{13}}{5*\frac{12}{13}} = \frac{\frac{27}{13}}{\frac{60}{13}} = \frac{27}{13} *\frac{13}{60}=\frac{9}{20}[/tex]
Szczegółowe wyjaśnienie:
