biết tan alpha = 12/35, tính sin alpha , cos alpha, cot alpha 20/07/2021 Bởi Amaya biết tan alpha = 12/35, tính sin alpha , cos alpha, cot alpha
$\cot\alpha=\dfrac{1}{\tan\alpha}=\dfrac{35}{12}$ $\dfrac{1}{\cos^2\alpha}=1+\tan^2\alpha$ $\Rightarrow \cos\alpha=\dfrac{35}{37}$ $\Rightarrow \sin\alpha=\sqrt{1-\cos^2\alpha}=\dfrac{12}{37}$ Bình luận
$\cot\alpha=\dfrac{1}{\tan\alpha}=\dfrac{35}{12}$
$\dfrac{1}{\cos^2\alpha}=1+\tan^2\alpha$
$\Rightarrow \cos\alpha=\dfrac{35}{37}$
$\Rightarrow \sin\alpha=\sqrt{1-\cos^2\alpha}=\dfrac{12}{37}$