Danh mục: Hỏi Đáp

\(B = \tan {10^0}.\tan {80^0} – \tan {20^0}.\tan {70^0}.\) A \(B=0\) B \(B=1\) C \(B = \frac{7}{2}\) D \(B =- \frac{7}{2}\) Hướng dẫn Chọn đáp …

\(A = {\sin ^2}{15^0} + {\sin ^2}{25^0} + {\sin ^2}{35^0} + {\sin ^2}{45^0} + {\sin ^2}{55^0} + {\sin ^2}{65^0} + {\sin ^2}{75^0}\) A \(A=0\) B …

\(cot\alpha = \frac{8}{{15}}\) A \(\tan \alpha = \frac{{15}}{8}\,\,;\,\,\sin \alpha = \frac{{15}}{{17}}\,\,;\,\,\cos \alpha = \frac{8}{{17}}\) B \(\tan \alpha = \pm \frac{{15}}{8}\,\,;\,\,\cos \alpha = \pm \frac{{15}}{{17}}\,\,;\,\,\sin \alpha …

Giá trị của biểu thức \(P = {\cos ^2}{20^0} + {\cos ^2}{40^0} + {\cos ^2}{50^0} + {\cos ^2}{70^0}\) bằng A \(0\) B \(1\) C \(2\) …

\({\rm{cos}}\alpha = \frac{3}{4}\) A \(\sin \alpha = \pm \frac{4}{5}\,\,;\,\,\tan \alpha = \pm \frac{{16}}{{15}}\,\,;\,\,\cot \alpha = \pm \frac{{15}}{{16}}\) B \(\sin \alpha = \frac{4}{5}\,\,;\,\,\tan \alpha = \frac{{16}}{{15}}\,\,;\,\,\cot …

\(\tan \alpha = \frac{{12}}{{35}}\) A \(\cot \alpha = \frac{{35}}{{12}}\,\,;\,\,\cos \alpha = \frac{{35}}{{37}}\,\,;\,\,\sin \alpha = \frac{{12}}{{37}}\) B \(\cot \alpha = \frac{{35}}{{12}}\,\,;\,\,\sin \alpha = \pm \frac{{35}}{{37}}\,\,;\,\,\cos \alpha …

\(\sin \alpha = \frac{5}{{13}}\) A \(\cos \alpha = \frac{{12}}{{13}}\,\,;\,\,\tan \alpha = \frac{5}{{12}}\,\,;\,\,\cot \alpha = \frac{{12}}{5}\) B \(\cos \alpha = \pm \frac{{12}}{{13}}\,\,;\,\,\tan \alpha = \pm \frac{5}{{12}}\,\,;\,\,\cot …

\(\tan \alpha = \frac{4}{3}\) A \(\sin \alpha = \pm \frac{4}{5}\,\,;\,\,\cos \alpha = \pm \frac{3}{5}\,\,;\,\,\cot \alpha = \frac{3}{4}\) B \(\sin \alpha = \frac{4}{5}\,\,;\,\,\cos \alpha = \frac{3}{5}\,\,;\,\,\cot …

\(\sin \alpha = \frac{2}{3}\) A \(\cos \alpha = \pm \frac{{\sqrt 5 }}{3}\,\,;\,\,\,\tan \alpha = \pm \frac{{2\sqrt 5 }}{5}\,\,;\,\,\,\cot \alpha = \pm \frac{{\sqrt 5 }}{2}\) B …

\({\rm{sin }}{49^o},{\rm{ cos }}{15^o},{\rm{ sin }}{65^o},{\rm{ cos }}{50^o},{\rm{ }}\cos {\rm{ }}{42^o}\) A \(\sin {49^0} < \sin {65^0} < \cos {15^0} < \cos {50^0} < \cos …