Exponent Extravagant

Algebra Level 3

Evaluate: 1^2 + 1^3 + 2^2 + 2^3 +...+ 199^2 + 199^3 + 200^2 + 200^3


The answer is 406696700.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Chew-Seong Cheong
Aug 13, 2014

Let S ( n ) = 1 2 + 1 3 + 2 2 + 2 3 + . . . + ( n 1 ) 2 + ( n 1 ) 3 + n 2 + n 3 S(n)=1^2+1^3+2^2+2^3+...+(n-1)^2+(n-1)^3+n^2+n^3 , then:

S ( n ) = i = 1 n i 2 + i = 1 n i 3 S(n) = \sum_{i=1}^{n}{i^2}+ \sum_{i=1}^{n}{i^3}

= 1 6 n ( n + 1 ) ( 2 n + 1 ) + 1 4 n 2 ( n + 1 ) 2 \quad = \frac{1}{6}n(n+1)(2n+1)+\frac{1}{4}n^2(n+1)^2

Therefore, S ( 200 ) = 1 6 ( 200 ) ( 201 ) ( 401 ) + 1 4 ( 20 0 2 ) ( 201 ) 2 S(200)= \frac{1}{6}(200)(201)(401)+\frac{1}{4}(200^2)(201)^2

= 2686700 + 404010000 = 406696700 \quad \quad \quad \quad \quad \quad \quad =2686700 + 404010000 = \boxed{406696700}

Rab Gani
Aug 13, 2014

1^2 +2^2+3^2 + ...+ 200^2 =1/6(200)(201+1)(2*201+1). And 1^3 +2^3+3^3+.....+ 200^3 = ((200)(201)/2)^2. And the total sum is 406696700

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...