If α,β are the acute angles of an obtuse-angled triangle, then tanαtanβ is
<1
>1
=1
None of these
Explanation for the correct option:
Find the value of tanαtanβ:
Given, α,β are the acute angles in an obtuse angled triangle
⇒ α+β<90°
⇒ tanα+β>0
⇒tanα+tanβ1–tanαtanβ>0
⇒ 1–tanαtanβ>0
⇒ tanαtanβ<1
Hence, Option ‘A’ is Correct.
If α and β are acute angles satisfying cos 2α=3 cos 2β−13−cos 2β, then tan α =