What is the sum of the squares of the first 20 natural numbers (1 to 20)?
2870
5650
2000
44100
Explanation:
Sum of squares of n numbers is given by the formula $\dfrac{n × (n + 1) (2n + 1)}{6}$
Here n = 20 so,
= $\dfrac{20 × (20+1)(2×20 + 1)}{6}$
= $\dfrac{20 × 21 × 41}{6}$
= $\dfrac{8610}{3}$
= 2870
So the sum of squares of first 20 terms is 2870.