
Chapter 13 Class 11 Limits and Derivatives
Chapter 13 Class 11 Limits and Derivatives
Last updated at Dec. 16, 2024 by Teachoo
Misc 24 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): (ax2 + sin x)( p + q cos x) Let f (x) = (ax2 + sin x) (p + q cos x) Let u = ax2 + sin x & v = p + q cos x ∴ f(x) = uv So, f’(x) = (𝑢𝑣)^′ Using product rule = 𝑢^′ 𝑣+〖 𝑣〗^′ 𝑢 Finding u’ & v’ u = ax2 + sin x u’ = (ax2 + sin x)’ = 2ax + cos x v = p + q cos x v’ = (p + q cos x)’ = 0 + q (– sin x) = – q sin x Now, f’(x) = 𝑢^′ 𝑣+〖 𝑣〗^′ 𝑢 = (2ax + cos x) (p + q cos x) + ( – q sin x) (ax2 + sin x) = – q sin x (ax2 + sin x) + (p + q cos x) (2ax + cos x) (xn)’ = n xn – 1 Derivative of sin x = cos x Derivative of cos x = – sin x Derivative of constant = 0