Bài tập theo tuần Toán 9 - Tuần 8 - Đề 2

 \(A{B}^{2}=BC.BH\)

 \(AB.AC=AH.BC\)

 \(A{H}^{2}=AB.AC\text{}\)

 \(\frac{1}{A{H}^{2}}=\frac{1}{A{B}^{2}}+\frac{1}{A{C}^{2}}\)

\({\mathrm{sin}}^{2}\alpha +{\mathrm{cos}}^{2}\alpha =1\)

\(\mathrm{cot}\alpha .\mathrm{tan}\alpha =1\)

\(\mathrm{tan}\alpha =\frac{\mathrm{sin}\alpha}{\mathrm{cos}\alpha}\)

\(\mathrm{sin}\alpha =\mathrm{cos}\left({90}^{0}-\beta \right)\)

\(\frac{AB}{AC}\)

 \(B.\frac{AB}{AC}\)

 \(C.\frac{HB}{AH}\)

\(\frac{BH}{AB}\)