NCERT Class 12 · Ch 5 Miscellaneous Exercise · Q19
NCERT Class 12 Maths · Chapter 5 Continuity And Differentiability · Miscellaneous Exercise Question 19
Differentiate sin(A+B)=sin A cos B+cos A sin B to obtain the cosine sum formula.
💡 Concept Hints
- Identify the domain and the inner and outer functions, or the relevant one-sided limits.
- Apply the appropriate differentiation or limit rule, keep all chain factors, and check exceptional points.
✅ Step-by-Step Solution
Final Answer: cos(A+B)=cos A cos B−sin A sin B.
- Hold B constant and differentiate both sides with respect to A.
- The left derivative is cos(A+B); the right is cos A cos B−sin A sin B.
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