1. Demonstrati ca in triunghiul ABC, dreptunghic in A, are loc egalitatea sin B +cos B=[tex] \frac{AB+AC}{BC} [/tex]
2. Demonstrati ca in triunghiul ABC,dreptunghic in A tg B=[tex] \frac{sinB}{cosB} [/tex]=[tex] \frac{1}{ctgB} } [/tex]si tg C=[tex] \frac{sinC}{cos C} } } [/tex]=[tex] \frac{1}{ctgC} } } } [/tex]