# Direct expression for sum of squares

1. Feb 19, 2006

### cscott

How do you go from $$\sum_{n = 1}^n i^2$$ to $$\frac{n(n + 1)(2n + 1)}{6}$$?

2. Feb 19, 2006

### arildno

Prove the formula by induction.

3. Feb 19, 2006

### dicerandom

I think you forgot to include something, what you wrote should simplify to $n i^2$.

Edit: Unless I'm missing something

4. Feb 19, 2006

### arildno

Oops, the index should be i, not n as you've written.

5. Feb 19, 2006

### 0rthodontist

6. Feb 19, 2006

### cscott

Thanks for the info.

My mistake with the index.