Find the sum of the firt 40 terms of the series `1^(2) -2^(2) + 3^(2) - 4^(2)`+……….

Find the sum of 1+3+5+…+ to 40 terms

The sum of first n terms of the series 1_(2) + 2.2^(2) + 3^(2) + 2.4^(2) + 5^(2) + 2.6^(2) + ...... is (n(n + 1)^(2))/4 when n is even. When n odd the sum is

Find the sum of the first n terms of the series 1/(sqrt(2) + sqrt(3)) + 1/(sqrt(3) + sqrt(4)) +...

Let A be the sum of the first 20 terms and B be the sum of the first 40 terms of the series 1^2+2.2^2+3^2+2.4^2+5^2+2.6^2+... If B-2A=100lambda then lambda is equal to (1) 232 (2) 248 (3) 464 (4)496

The sum to first 25 terms of the series 1+2+3+"…………" is

Find the sum to n terms of the series 1^2+2^2+3^2-4^2+5^2-6^2+. . . .

Find the sum to n terms of each of the series in 3 × 1^(2) + 5 × 2^(2) + 7 × 3^(2) +.........