Question

срочно помогите 25 балов​

Answer 1

$AB^2=AC^2+CB^2 \\ \\ CB^2= AB^2-AC^2 \\ \\ CB=\sqrt{AB^2-AC^2}=\sqrt{20^2-11^2}=\sqrt{(20-11)\cdot(20+11)}=\sqrt{9\cdot31}=3\sqrt{31} \\ \\ \sin{\angle A}=\frac{CB}{AB}=\frac{3\sqrt{31}}{20} \\ \\ \sin {\angle B} =\frac{AC}{AB}=\frac{11}{20} \\ \\ \cos{\angle A}=\frac{AC}{AB}=\frac{11}{20} \\\\ \cos{\angle B}=\frac{CB}{AB}=\frac{3\sqrt{31}}{20}$