1. ## series

I think i found the bottom one, 2n+3 the only way i can see the top one is in a recursive but i need a closed form, can anyone give me some hints on how to look at it...

Find a formula for sn, n 1. , , , , , , ...

2. numerator looks to be $n!$

3. ## He's right!

yes, the general term is n! / (2n+3);

4. Originally Posted by acosta0809
I think i found the bottom one, 2n+3 the only way i can see the top one is in a recursive but i need a closed form, can anyone give me some hints on how to look at it...

Find a formula for sn, n 1. , , , , , , ...
The numerator is $n! = n\cdot (n-1)\cdot (n-2) \cdot \dots \cdot 3 \cdot 2 \cdot 1$.

So $t_n = \frac{n!}{2n + 3}$

$S_n = \sum_{i = 1}^n \frac{n!}{2n + 3}$.

If this was an infinite series, it would diverge btw. But since it's finite, that's a bit trickier...