Evaluate the following limit : lim(n→∞) n sin(π/4n) cos(π/4n) - Sarthaks eConnect | Largest Online Education Community
Solved Let an = cos (pi/n). Does the sequence {an} converge? | Chegg.com
real analysis - How to prove that $\lim(\underset{k\rightarrow\infty}{\lim}(\cos(|n!\pi x|)^{2k}))=\chi_\mathbb{Q}$ - Mathematics Stack Exchange
sequences and series - Using roots of unity to prove that $\cos\frac{\pi }{2n}\cos\frac{2\pi}{2n}\cdots\cos\frac{(n-1)\pi}{2n}=\frac{\sqrt{n}}{2^{n-1}}$ - Mathematics Stack Exchange
If S=cos^2(pi/n)+cos^2((2pi)/n)+....+cos^2(((n-1)pi)/(n)), then S equals