Explanation: 
Another Explanation (5):
sin 50° - sin 70° + sin 10° এর মান নির্ণয়:
আমরা জানি, \(sin C - sin D = 2 cos(\frac{C+D}{2}) sin(\frac{C-D}{2})\)
এখানে, C = 50° এবং D = 70°
অতএব, sin 50° - sin 70° = \(2 cos(\frac{50°+70°}{2}) sin(\frac{50°-70°}{2})\)
= \(2 cos(60°) sin(-10°)\)
= \(2 \times \frac{1}{2} \times (-sin 10°)\) [∵ cos 60° = \(\frac{1}{2}\) এবং sin(-θ) = -sin θ]
= - sin 10°
সুতরাং, sin 50° - sin 70° + sin 10° = - sin 10° + sin 10° = 0
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