Question

$\sin( \frac{5\pi}{6} + a ) + \sin( \frac{5\pi}{6} - a )$
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Answer 1

$\textbf{formula used :-}$

$\bf\boxed{sin(A+B)+sin(A-B)=2 sinA\: cosB}$

= $\bf\:2 sin(5\pi/6) . cosA$

=$\bf\: 2 sin(\pi-\pi/6) . cosA$

= $\bf\:2 sin(\pi/6) . cosA$

= 2 (1/2) . cosA

= $\boxed{cosA}$

Answer 2

Answer:

sin5pie\6(1+1+a-a)

sin5\6 * 22\7 * 2

sin110\21

sin5.238

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