Find the value of $\cos(2\pi /5)$ using radicals
30429
How to prove $\cos \frac{2\pi }{5}=\frac{-1+\sqrt{5}}{4}$?
19475
Evaluate$\int_{-2}^2\int_{y^2-3}^{5-y^2}dxdy$
122169
Prove $\sin(\pi/2)=1$ using Taylor series
76490
Proving that $\cos(\arcsin(x))=\sqrt{1-x^2}$
118408
Equation with cos and product
29517
How to find continued fraction of pi
97582
How do I evaluate this integral $\int_0^\pi{\frac{{{x^2}}}{{\sqrt 5-2\cos x}}}\operatorname d\!x$?
108245
Solving the complex equation $\sin(z) = \cos(z)$
90185
Another way to evaluate $\int\frac{\cos5x+\cos4x}{1-2\cos3x}{dx}$?
14386
Proof of an equality involving cosine $\sqrt{2 + \sqrt{2 + \cdots + \sqrt{2 + \sqrt{2}}}}\ =\ 2\cos (\pi/2^{n+1})$
158210
showing $\arctan(\frac{2}{3}) = \frac{1}{2} \arctan(\frac{12}{5})$
107067
Finding the argument of $z=1-\cos(2\theta)-i\sin(2\theta)$
130686
How is $3\pi-10$ element of $[-\pi/2,\pi/2]$?
59818
Why $(-2)^{2.5}$ isn't equal to $((-2)^{25})^{1/10}$?
120953
Show that, $2\arctan\left(\frac{1}{3}\right)+2\arcsin\left(\frac{1}{5\sqrt2}\right)-\arctan\left(\frac{1}{7}\right)=\frac{\pi}{4}$
22512
Find the value of: $\frac{\sqrt{45} + \sqrt{18}} {\sqrt{7+2\sqrt{10}}}$
83359
Complex number identity by trigonometry