Ta có:
+/ \(\sin^2\alpha+\cos^2\alpha=1\)
\(\Rightarrow\dfrac{9}{25}+\cos^2\alpha=1\)
\(\Rightarrow\cos^2\alpha=\dfrac{16}{25}\)
\(\Rightarrow\cos\alpha=\dfrac{4}{5}\)
+/ \(\tan\alpha=\dfrac{\sin\alpha}{\cos\alpha}=\dfrac{\dfrac{3}{5}}{\dfrac{4}{5}}=\dfrac{3}{4}\)
+/ \(\tan\alpha.\cot\alpha=1\)
\(\Rightarrow\dfrac{3}{4}.\cot\alpha=1\)
\(\Rightarrow\cot\alpha=\dfrac{4}{3}\)
Vậy \(\cos\alpha=\dfrac{4}{5}\), \(\tan\alpha=\dfrac{3}{4}\), \(\cot\alpha=\dfrac{4}{3}\)
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