A function f ( x ) is given by f x = 5 x 5 x + 5 , then the sum of the series f 1 20 + f 2 20 + f 3 20 + … + f 39 20 is equal to:

Question

A function f ( x ) is given by f x = 5 x 5 x + 5 , then the sum of the series f 1 20 + f 2 20 + f 3 20 + … + f 39 20 is equal to:, 19 2, 49 2, 39 2, 29 2

MARKS App · Accepted Answer

f x = 5 x 5 x + 5 and f 2 - x = 5 5 x + 5 f x + f 2 - x = 1 ⇒ f 1 20 + f 2 20 + … + f 39 20 = f 1 20 + f 39 20 + … + f 19 20 + f 21 20 + f 20 20 = 19 + 1 2 = 39 2

Search any question & find its solution

Looking for more such questions to practice?