Sum to n terms 6 +66 + 666 + ………..

Find the sum of the following series up to n terms: .6+. 66 +. 666+...

Sum to n terms : 4+ 44+ 444 + ............

Sum to n terms: 9+ 99 + 999 + ......

If the sum to 2n terms of the A.P. 2, 5, 8, 11, .... is equal to the sum to n terms of 57, 59, 61, 63, ....., then n=

Sum to n terms: 3 + 33+ 333 +..........

Sum to n terms: 8 + 88 + 888+..........

Sum to n terms the series : 1^2 - 2^2 + 3^2 - 4^2 + 5^2 - 6^2 + ...

Find the sum of n terms of the AP 6,13,20.....

Find the nth term and the sum of n terms of the series : 6 +9 +21 + 69 + 261 + ....