Question

nếu \(tan\alpha+cot\alpha=4\) thì \(tan^2\left(\alpha+3\pi\right)+tan^2\left(\alpha+\frac{3\pi}{2}\right)=?\)

Answer 1

\(\left(tana+cota\right)^2=16\)

\(\Leftrightarrow tan^2a+cot^2a+2=16\)

\(\Rightarrow tan^2a+cot^2a=14\)

\(tan^2\left(a+3\pi\right)+tan^2\left(a+\frac{3\pi}{2}\right)=tan^2a+cot^2a=14\)