Is there a geometric proof of $ \sin(3t) = 3\sin(t) - 4\sin^3(t) $
63679
Picture/intuitive proof of $\cos(3 \theta) = 4 \cos^3(\theta)-3\cos(\theta)$?
97213
Why does $\sin(0)$ exist?
86454
How to prove $\cos\left(\pi\over7\right)-\cos\left({2\pi}\over7\right)+\cos\left({3\pi}\over7\right)=\cos\left({\pi}\over3 \right)$
51979
Is there a geometrical method to prove $x<\frac{\sin x +\tan x}{2}$?
82913
Is this a proof of Fermat's Last Theorem where n = 3?
54175
Prove the trigonometric identity $\sin^4{x} = \frac{3-4\cos{2x}+\cos{4x}}{8}$
142835
Proving :$\arctan(1)+\arctan(2)+ \arctan(3)=\pi$
136894
Reference request: Clean proof of Fermat's last theorem for $n=3$.
153043
Show that $\sqrt{4+2\sqrt{3}}-\sqrt{3}$ is rational using the rational zeros theorem
120795
Showing that $\sin^2x\cdot\sin^22x\cdot\sin^24x\cdot\sin^28x\cdots\sin^22^nx\leq\frac{3^n}{4^n}$
55436
Why does $A\sin{k(x+c)}=a\sin{kx}+b\cos{kx}$ imply that $A=\sqrt{a^2+b^2}$ and $\tan{c}=-b/a$?
129443
$f(\theta) = \cos \theta - \sqrt{3}\sin \theta$ in the form $r\sin(\theta-\alpha)$
34049
How can I understand and prove the "sum and difference formulas" in trigonometry?
12158
Show that $\arctan\frac{1}{2}+\arctan\frac{1}{3}=\frac{\pi}{4}$
96354
Linear independence of $\sin(x)$, $\sin(2x)$, $\sin(3x)$ in Map($\mathbb{R},\mathbb{R}$)
143072
Proving $|\sin x - \sin y| < |x - y|$
105487
Prove that $\sin x \cdot \sin (2x) \cdot \sin(3x) < \tfrac{9}{16}$ for all $x$