(Summation) of r.r! r=1 to n Share with your friends Share 0 Vipin Verma answered this ∑r=1nr.r!This is a series of 1.1! + 2.2! + 3.3! +.............................n.n!Here we can write 2.2! = ((2+1)-1)2! = (2+1)! -2! = 3!-2!For 3.3! = (3+1)! -3! = 4!-3!Hence we can write the above expression as (2!-1!) + (3!-2!) + (4!-3!) ...............................(n+1)! -n!= (n+1)! -1 (ans) -2 View Full Answer
