Question

Cho cos anpha  = \(\frac{2}{3}\)tính các tỉ số lượng giác góc anpha

Answer 1

+\(cos^2\alpha+sin^2\alpha=1\Rightarrow sin^2\alpha=1-cos^2\alpha=1-\frac{4}{9}=\frac{5}{6}\Rightarrow sin\alpha=\pm\sqrt{\frac{5}{6}}\)

+\(tan\alpha=\frac{sin\alpha}{cos\alpha}=\frac{\pm\sqrt{\frac{5}{6}}}{\frac{2}{3}}\)

+\(cotg\alpha=\frac{1}{tan\alpha}=\frac{\frac{2}{3}}{\pm\sqrt{\frac{5}{6}}}\)