08-08-2014, 11:26 PM
what is the sum of 1^2+3^2+5^2+....31^2 ?
a) 9455
b) 5456
c) 3468
d) 4892
answer choice b
solution
1^2+2^2+3^2......n^2 = (n(n+1)(2n+1))/6
expression = ((31*32*63)/6)-((60*16*31)/6)
=5456
a) 9455
b) 5456
c) 3468
d) 4892
answer choice b
solution
1^2+2^2+3^2......n^2 = (n(n+1)(2n+1))/6
expression = ((31*32*63)/6)-((60*16*31)/6)
=5456