Property 2

Q.

If $x_n$ = cos( $\frac{\pi }{4^n}$) + i sin( $\frac{\pi }{4^n}$) then $x_1{x}_2{x}_3.........\infty =$

1. 

2. 

3. 

4. 

Q. The value of the integral $\underset{4}{\overset{10}{\int }}\frac{\left[x^2\right]}{[x^2-28x+196]+\left[x^2\right]}dx,$ where $\left[x\right]$ denotes the greatest integer less than or equal to $x$, is