Evaluate $ \cos(x) \cos(2x) \cos(3x) ... \cos(999x) $ where $x = \frac{2 \pi}{ 1999 }$.
60774
Find the value of : $\cos x \cos 2x...\cos 999x$ given that $x=\frac {2\pi}{1999}$
82586
Why is cos -x equal to cos x?
151063
Calculate $\int_{0}^{\frac{\pi}{2}}\frac{\sin^{3}(t)}{\sin^{3}(t)+\cos^{3}(t)}dt$ by hands
65698
Proving $\sum\limits_{k=0}^{n}\cos(kx)=\frac{1}{2}+\frac{\sin(\frac{2n+1}{2}x)}{2\sin(x/2)}$
105496
Need help solving - $ \int (\sin 101x) \cdot\sin^{99}x\,dx $
51488
Evaluating $\int^\pi_{-\pi} \cos^3(x) \cos(ax)~dx$
106828
If $0 \lt x \lt \frac{\pi}{2}$, is $\cos(x) \le \frac{\sin(x)}{x} \le \frac{1}{\cos(x)}$?
142114
Limit as $x\to 2$ of $\frac{\cos(\frac \pi x)}{x-2} $
104542
Evaluate $\frac{1}{3}+\frac{1}{4}\frac{1}{2!}+\frac{1}{5}\frac{1}{3!}+\dots$
65028
Evaluate $\int\frac {\csc^2{x}-2005}{\cos^{2005}{x}} dx $
95403
Evaluating $\int \frac{\sec^2 x}{(\sec x + \tan x )^{{9}/{2}}}\,\mathrm dx$
26096
Evaluating $\int \frac{\sin{x}+\cos{x}}{\sin^4{x}+\cos^4{x}} \mathrm dx$
71700
How to solve $\int_0^\pi{\frac{\cos{nx}}{5 + 4\cos{x}}}dx$?
23091
Compute cos(5°) to 5 decimal places with Maclaurin's Series
46353
Proof that $\cos(\pi/3)=1/2$
117200
Evaluation of $ \sum_{k=0}^n \cos k\theta $
106544
Solve $ \frac{2}{\pi}\int_{-\pi}^\pi\frac{\sin\frac{9x}{2}}{\sin\frac{x}{2}}dx $