Solving for an angle in an $80^\circ$-$80^\circ$-$20^\circ$ triangle ($60^\circ$-$70^\circ$ variant)
40615
Solve for $x$ in the $80^\circ$-$80^\circ$-$20^\circ$ triangle
40063
$x^2+y^2=z^n$: Find solutions without Pythagoras!
12414
prove that : $\cos x \cdot \cos(x-60^{\circ}) \cdot \cos(x+60^{\circ})= \frac14 \cos3x$
125171
Help with this trigonometry problem?
149447
Proving $\sin (x)=\cos (90^\circ-x)$
33396
Generalizing a Trig Identity
103988
Prove that $\tan20^°\tan40^°\tan60^°\tan80^°=3$
102320
Is my solution correct for solving $\cos(z)=2$, $z\in \mathbb{C}$
146308
Solving 2-degree equations in 3 variables.
73799
In a convex Quadrilateral ABCD, $\measuredangle ABC = \measuredangle BCD = 120^{\circ}$.Prove that: $ AC + BD \ge AB + BC + CD$
54512
How do I prove: $\cos (\theta + 90^\circ) \equiv - \sin \theta $
125597
calculator's angle answer for trig ratios that can work in more than 1 quadrant on the unit circle
88283
Proving the length of angle bisector
40596
Proving a relation between inradius ,circumradius and exradii in a triangle
87304
Solving for $x$ : $a^x+b^x=c$
9479
$\sum \cos$ when angles are in arithmetic progression
73538
solving $\cos z + \sin z = i$