Misc 14 - Find derivative: sin (x + a) - Class 11 CBSE NCERT

Misc 14 - Chapter 13 Class 11 Limits and Derivatives - Part 2

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Misc 14 Find the derivative of the following functions (it is to be understood that a, b, c, d, p, q, r and s are fixed non-zero constants and m and n are integers): sin (x + a) Let f(x) = sin (x + a) Using sin (A + B) = sin A cos B + cos B sin A = sin x . cos a + cos x . sin a = cos a (sin x) + sin a (cos x) So, f’(x) = (cos a (sin x) + sin a (cos x))’ = (cos a (sin x))’ + (sin a (cos x))’ = cos a (sin x)’ + sin a (cos x)’ = cos a cos x + sin a ( – sin x) = cos a cos x – sin a sin x Derivative of sin x = cos x Derivative of cos x = – sin x = cos a cos x – sin a sin x = cos (a + x) = cos (x + a) Hence f’(x) = cos (x + a) Using cos (A + B) = cos A cos B – Sin A sin B

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.