Solution 1:
You are almost there.
Note that $$ (n+1)! - 1 + (n+1)(n+1)! = -1 + (n+1)!( 1 + (n+1) ) = -1+ (n+2)(n+1)! = (n+2)! - 1. $$
Simplify sum of factorials with mathematical induction
Solution 1:
You are almost there.
Note that $$ (n+1)! - 1 + (n+1)(n+1)! = -1 + (n+1)!( 1 + (n+1) ) = -1+ (n+2)(n+1)! = (n+2)! - 1. $$