Question

find the derivative of 5 sec x + 4 cos x NOT from first principle​

Answer 1

Answer:

let  f (x) = 5 sec x  +  4 cos x.

now,

f' (x) = (5 sec x + 4 cos x)'

       = (5 sec x)' + (4 cos x)'

       = 5 (sec x . tan x) + 4 (- sin x)

       = 5 sec x . tan x - 4 sin x