defence exam Agniveer Vayu Group X & XY Mock Test 01/2026 Mathematics Trigonometry Multiple and Sub-multiple Angles
In \(\triangle ABC\), with usual notations, if \(a,b,c\) are in A.P then \(a\cos ^{ 2 }{ \left( \cfrac { C }{ 2 } \right) } +c\cos ^{ 2 }{ \left( \cfrac { A }{ 2 } \right) } =\)
1
\(3\cfrac { a }{ 2 } \)
2
\(3\cfrac { c }{ 2 } \)
3
\(3\cfrac { b }{ 2 } \)
4
\(\cfrac { 3abc }{ 2 } \)