How to evaluate cos(2$\pi$/5)?
30429
How to prove $\cos \frac{2\pi }{5}=\frac{-1+\sqrt{5}}{4}$?
106803
How to see $\cos x \leq \exp(-x^2/2)$ on $x \in [0,\pi/2]$?
55179
How to find the exact value of $ \cos(36^\circ) $?
71982
Evaluating this integral $ \small\int \frac {x^2 dx} {(x\sin x+\cos x)^2} $
23727
How can I deduce $\cos\pi z=\prod_{n=0}^{\infty}(1-4z^2/(2n+1)^2)$?
97582
How do I evaluate this integral $\int_0^\pi{\frac{{{x^2}}}{{\sqrt 5-2\cos x}}}\operatorname d\!x$?
5747
$\cos(\arcsin(x)) = \sqrt{1 - x^2}$. How?
19475
Evaluate$\int_{-2}^2\int_{y^2-3}^{5-y^2}dxdy$
60491
Evaluate $ \int_{25\pi/4}^{53\pi/4}\frac{1}{(1+2^{\sin x})(1+2^{\cos x})}dx $
105774
How is $ \cos (\alpha / \beta) $ expressed in terms of $\cos \alpha $ and $ \cos \beta $?
104542
Evaluate $\frac{1}{3}+\frac{1}{4}\frac{1}{2!}+\frac{1}{5}\frac{1}{3!}+\dots$
156485
How to evaluate $\int_{0}^{2\pi}e^{\cos \theta}\cos( \sin \theta) d\theta$?
124401
How to evaluate $\int_0^{2\pi}\frac{1}{(1+a\cos {\theta})^2}\,d\theta$ without contour integration?
51787
Evaluate $\int \cos(3x) \sin(2x) \, dx$.
24670
Find $x$: $5\cos(x) = 2\sec(x)-3$
64417
Integration of $\int \frac{x^2+20}{(x \sin x+5 \cos x)^2}dx$
134633
How to sum this series for $\pi/2$ directly?