Question

1²+3²+5²+......+17²=k*19, then the value of k

Answer 1

formula-

=> 1²+3²+5²+........+(2n-1)²=n/3(2n+1)(2n-1)

where n=number of terms

now, put n=9,

=> 1²+3²+.......+17²=9/2(19)(17)=(153/2).19

so,k=153/2