Find the sum of:- 1.1!+2.2!+3.3!+..............+n.n!
Answers
Answered by
74
We have to first arrange it like this -
Sum = (2-1).1! + (3-1).2! + (4-1).3!...............+(n+1-1).n!
=2.1! - 1.1! + 3.2! - 1.2! + 4.3! - 1.3!.............(n+1)n! - 1n!
=2! - 1! + 3! - 2! +4! - 3! + ................(n+1)! - n!
=(n+1)! - 1
Sum = (2-1).1! + (3-1).2! + (4-1).3!...............+(n+1-1).n!
=2.1! - 1.1! + 3.2! - 1.2! + 4.3! - 1.3!.............(n+1)n! - 1n!
=2! - 1! + 3! - 2! +4! - 3! + ................(n+1)! - n!
=(n+1)! - 1
Answered by
10
Answer:
Sum = (2-1).1! + (3-1).2! + (4-1).3!...............+(n+1-1).n!
=2.1! - 1.1! + 3.2! - 1.2! + 4.3! - 1.3!.............(n+1)n! - 1n!
=2! - 1! + 3! - 2! +4! - 3! + ................(n+1)! - n!
=(n+1)! - 1
Step-by-step explanation:
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