If the function f x = 1 x log e 1 + x a 1 - x b , x < 0 k , x = 0 cos 2 x - sin 2 x - 1 x 2 + 1 - 1 , x > 0 is continuous at x = 0 , then 1 a + 1 b + 4 k is equal to :

Step-by-step solution

Given that f x = 1 x log e 1 + x a 1 - x   b                     ,   x < 0 k                                                                         ,   x = 0 cos 2 x - sin 2 x - 1       x 2 + 1 - 1         ,   x > 0 f x is con