Nếu tan x = 0.5 ; sin y = 3/5 ( 0 < y < 90 độ ) thì tan ( x + y ) bằng:

8/22

Nếu \(\tan x = 0.5;\,\,\sin y = \frac{3}{5}\,\,\left( {0 < y < {{90}^0}} \right)\) thì \(\tan \left( {x + y} \right)\) bằng:

\[2\].

\(3\).

\(4\).

\(5\).

Giải thích

Chọn A

\(\tan x = 0.5 = \frac{1}{2},\,\sin y = \frac{3}{5}\,\,\left( {0 < y < {{90}^0}} \right) \Rightarrow \cos y = \frac{4}{5} \Rightarrow \tan y = \frac{3}{4}\).

\(\tan \left( {x + y} \right) = \frac{{\tan x + \tan y}}{{1 - \tan x.\tan y}} = \frac{{\frac{1}{2} + \frac{3}{4}}}{{1 - \frac{1}{2}.\frac{3}{4}}} = 2\).