
Miscellaneous
Last updated at Dec. 16, 2024 by Teachoo
Transcript
Misc 25 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): (x + cos x) (x tan x) Let f (x) = (x + cos x) (x tan x) Let u = x + cos x & v = x tan x f(x) = uv So, f (x) = Using product rule f (x) = + Finding u & v u = x + cos x u = (x + cos x) = 1 sin x & v = x tan x v = (x tan x) = 1 sec2 x Now, f (x) = = + = (1 sin x) (x tan x) + (1 sec2 x) (x + cos x) = (1 sin x) (x tan x) (sec2 x 1) (x +cos x) = (1 sin x) (x tan x) tan2x (x + cos x) = tan2x (x + cos x) + (x tan x) (1 sin x)