Evaluate the value of : `A=3/(1!+2!+3!)+(4!)/(2!+3!+4!)+......+n/((n-2)!+(n-1)!+n!)`

 Evaluate the value of : 

1. `A=3/(1!+2!+3!)+(4!)/(2!+3!+4!)+......+n/((n-2)!+(n-1)!+n!)`

Solution: