If, in a triangle, , then its sides are…

MATHEMATICS · Single correct · IB Diploma Programme · Mathematics: Analysis and Approaches · Geometry and Trigonometry · Geometry and Trigonometry

Problem

If, in a triangle,

a\cos^2\frac{C}{2} + c\cos^2\frac{A}{2} = \frac{3b}{2}

, then its sides are in (1) AP (2) GP (3) HP (4) AGP