448

You visited us 448 times! Enjoying our articles? Unlock Full Access!

Sum of N Terms of an AP

Find the sum ...

Question

Find the sum of first $20$ terms of the series $1 + 2 + 3 +$ ........

Open in App

Solution

The given series is that of natural numbers. Hence, we can find the sum using the relation.
$S_{n} = \frac{n (n + 1)}{2}$ here, n = 20
$S_{20} = \frac{20 (20 + 1)}{2} = \frac{20 \times 21}{2}$
$S_{20} = 210$

Suggest Corrections

Similar questions

40

1^{2} - 2^{2} + 3^{2} - 4^{2} + . . . . .

S = 1 + \frac{1}{2} + \frac{1}{4} + \frac{1}{8} + . . .

20

n

5

1 + \frac{2}{3} + \frac{4}{9} + \dots

n

5

1 + \frac{2}{3} + \frac{4}{9} + . . .

A

20

B

40

1

{2.2}^{2}

3^{2}

{2.4}^{2}

5^{2} + {2.6}^{2}

A

Join BYJU'S Learning Program