In any `Delta` ABC,`sum` a sin (B -C) =

Options

A. 2s
B. a+b+c
C. `a^(2)+b^(2)+c^(2)`
D. 0

Explanation

To solve the problem, we need to find the value of the expression \( \sum A \sin(B - C) \) in any triangle \( ABC \). Here’s the step-by-step solution:

### Step 1: Use the Sine Rule
According to the sine rule, we have:
\[ \frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C} = k \]
where \( a, b, c \) are the lengths of the sides opposite to angles \( A, B, C \) respectively, and \( k \) is a constant.
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