In a `DeltaABC ,a cos^(2)(B/2)+bcos^(2)(A/2)` is equal to

Options

A. s
B. 2s
C. s/2
D. none of these

Explanation

To solve the problem \( a \cos^2\left(\frac{B}{2}\right) + b \cos^2\left(\frac{A}{2}\right) \) in triangle \( \Delta ABC \), we can follow these steps:

### Step 1: Use the half-angle cosine formulas
We know the formulas for \( \cos\left(\frac{B}{2}\right) \) and \( \cos\left(\frac{A}{2}\right) \):
\[ \cos\left(\frac{B}{2}\right) = \sqrt{\frac{s(s-b)}{ac}} \]
\[
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