Question

[Khổng Tử]

giúp mình giải chi tiết với

Answer 1

[Nguyễn Tất Đạt]

\(\cot\alpha=\frac{1}{2}\Rightarrow\tan\alpha=2\)

\(\Rightarrow\frac{1}{\cos^2\alpha}=1+\tan^2\alpha=5;\frac{1}{\sin^2\alpha}=1+\cot^2\alpha=\frac{5}{4}\)

\(\Rightarrow\cos^2\alpha=\frac{1}{5};\sin^2\alpha=\frac{4}{5}\)

\(P=\sin^2\left(\pi-\alpha\right).\sin\left(\frac{\pi}{2}-\alpha\right).\cos\alpha\)

\(=\sin^2\alpha.\cos^2\alpha=\frac{4}{25}\)