New posts in Trigonometry

$\arccos(1/2)$ products

How do we solve the equation $3\sec^{2}(x) - 4 = 0$?

Show that $\sqrt{\frac{1+2\sin\alpha\cos\alpha}{1-2\sin\alpha\cos\alpha}}=\frac{1+\tan\alpha}{\tan\alpha-1}$

What's the most elementary way to solve this trigonometric problem?

Elementary proof (involving no series expansion) that $\tan x \approx x+\frac{x^3}{3}$ for small $x$

How do we show $1-\cos x\ge\frac{x^2}3$ for $|x|\le1$?

A square appears randomly within a square of ten time its area. What is probability that the smaller square contains the larger square's center?

$\frac{d}{dx}(\sin(x^{\frac{1}{3}}))$ from first principle

Solve $\sin(3x)\sin(4x)=\cos(4x)\cos(5x)$ (problem from a Swedish 12th grade ’Student Exam’ from 1931)

$\lim_{x \to 0}{\frac{\sinh(x)-\sin(x)}{x(\cosh(x)-\cos(x))}}$