Misc 23 - Find derivative: (x2 + 1) cos x - Class 11 NCERT - Derivatives by formula - sin & cos

Misc 23 - Chapter 13 Class 11 Limits and Derivatives - Part 2

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Misc 23 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): (x2 + 1) cos x Let f (x) = (x2 + 1) cos x Let u = (x2 + 1) & v = cos x f(x) = uv So, f (x) = Using product rule f (x) = + Finding u & v u = x2 + 1 u = 2. x2 1 + 0 = 2x & v = cos x v = sin x Now, f (x) = = + = 2x ( cos x) + ( sin x) (x2 + 1) = 2x cos x sin x (x2 + 1) = 2x cos x2 sin x sin x = x2 sin x sin x + 2x cos x

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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.