Question

Let $\sum _ { r = 1 } ^ { n } r ^ { 4 } = f ( n )$ , then is equal to

• A. f(2n) – 16 f(n)
• B. f (2n) – 7f (n)
• C. f(2n – 1) – 8 f(n)
• D. None of these

Answer 1

Answer: (A)

f(2n) – 16 f(n)

Answer 2

We have

= f(2n) – 16f(n)