Sum of n terms of the series is A mathematical series showing the sum of square roots of numbers: square root of 2 + square root of 8 + square root of 18 + square root of 32 + ...

Q20 of 202 Page 10

Sum of n terms of the series is

The given A.P is

_{The simplified A.P is}

Here a=

d= =

S_n = (2a + (n–1) d)

= (2 + (n–1))

= /2 (1 + n)

= n (n + 1)/

If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 terms is

The number of terms of the A.P. 3, 7, 11, 15, ... to be taken so that the sum is 406 is

The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is

If are in A.P. Then, x =