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