sin(A-30°)+sin(A+150°)=? 

Explanation:

Another Explanation (5): sin(A-30°) + sin(A+150°) = ? আমরা জানি, sin(C) + sin(D) = 2sin((C+D)/2)cos((C-D)/2) 🤓 এখানে, C = A-30° এবং D = A+150° তাহলে, sin(A-30°) + sin(A+150°) = 2sin(((A-30°) + (A+150°))/2)cos(((A-30°) - (A+150°))/2) 🥳 = 2sin((2A+120°)/2)cos((-180°)/2) = 2sin(A+60°)cos(-90°) 😎 যেহেতু cos(-90°) = 0, সুতরাং 🧐 2sin(A+60°)cos(-90°) = 2sin(A+60°) * 0 = 0 অতএব, sin(A-30°) + sin(A+150°) = 0 🥰