1. ## Evaluate the sum

1.Find the sum upto first n-terms of the series

$\displaystyle \frac{1}{4}+\frac{1.3}{4.6}+\frac{1.3.5}{4.6.8}+.. ..$

2.Evaluate

$\displaystyle \sum_{n=1}^{\infty}\left(\frac{\tan \frac{\theta}{2^n}}{2^{n-1}\cos \frac{\theta}{2^{n-1}}}\right)$

2. Originally Posted by pankaj
1.Find the sum upto first n-terms of the series

$\displaystyle \frac{1}{4}+\frac{1.3}{4.6}+\frac{1.3.5}{4.6.8}+.. ..$

2.Evaluate

$\displaystyle \sum_{n=1}^{\infty}\left(\frac{\tan \frac{\theta}{2^n}}{2^{n-1}\cos \frac{\theta}{2^{n-1}}}\right)$
For #1, what do you mean by 1.3.5 and 4.6.8?

3. it's a product.

4. Originally Posted by Krizalid
it's a product.
Ok, yeah sorry. The placement of the dot as a period rather than a middle height threw me off.