Interesting SUM: Can you solve it? #maths

#brainexercise #matholympics
Interesting SUM: Can you solve it? #maths

Comment your answer in the comment section down below

[raghvendrasingh]

❤
third method
Let (k+1)^3 = ak(k-1)(k-2)+bk(k-1)+ck+d
Putting k = 0
d = 1
putting k = 1
8 = c+d hence c = 7
putting k = 2
27 = 2 b+2 c+d hence b = 6
comparing coefficient of k^3 both sides a = 1
using this expression for (k+1)^3 we get 4 series
1st series is summation 1/(k - 3)! , k =
hence sum is e
similarly sum of 2nd, 3rd & 4 series = 6 e, 7 e, e respectively.
total sum = 15 e