sin(A + B) is equal to:
Asin A cos B − cos A sin B
Bcos A cos B + sin A sin B
Ccos A cos B − sin A sin B
Dsin A cos B + cos A sin B
Answer & Solution
Correct answer: D. sin A cos B + cos A sin B
1. Addition formula: sin(A + B) = sin A cos B + cos A sin B.
2. The cos formulas: cos(A + B) = cos A cos B − sin A sin B; cos(A − B) = cos A cos B + sin A sin B.
3. Sign rules: 'sin' formulas have + between products; 'cos' formulas reverse sign.
_Source: NCERT Class 11 Maths Ch 3 §3.4 Sum and Difference Formulas_
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