Question

Fie un triunghi abc cu ab=9cm,bc=12 cm si ac=7 cm.Sa se determine sinus B,cosinus B,tangenta B,cotangenta B.

Answer 1

cosB = $\frac{AB^2 + BC^2 - AC^2}{2AB*BC}= \frac{81+144-49}{y} = \frac{176}{216}= 0.814$
sinB = √(1-cos²B) = √(1-0.665) =√0.335=0.578
tgB = $\frac{sinB}{cosB}$=$\frac{0.578}{0.814}$ = 0.71
ctgB = $\frac{1}{0.71}$ = 1.408