Cho \(\sin \alpha  = \frac{3}{5}\left( {{{90}^0} &...

Câu hỏi: Cho \(\sin \alpha  = \frac{3}{5}\left( {{{90}^0} < \alpha  < {{180}^0}} \right)\). Tính \(\cot \alpha .\)

A. \(\cot \alpha  = \frac{3}{4}.\)

B. \(\cot \alpha  = \frac{4}{3}.\)

C. \(\cot \alpha  = \frac{-4}{3}.\)

D. \(\cot \alpha  = \frac{-3}{4}.\)