biết tan alpha = 12/35, tính sin alpha , cos alpha, cot alpha

$\cot\alpha=\dfrac{1}{\tan\alpha}=\dfrac{35}{12}$

$\dfrac{1}{\cos^2\alpha}=1+\tan^2\alpha$

$\Rightarrow \cos\alpha=\dfrac{35}{37}$

$\Rightarrow \sin\alpha=\sqrt{1-\cos^2\alpha}=\dfrac{12}{37}$