Geometry problem prove $\angle{ADB}=3\angle{BAC}$
37233
Find the condition in which $\angle ADB = 3\angle BAC$
135543
Proof of Angles going beyond 90 degrees in Trigonometry
102742
order $a$ = 5, $a^3b = ba^3$. show that that $ab = ba$.
143801
Proving the AGM inequality with 3 variables
6410
Prove that $(ma, mb) = |m|(a, b)\ $ [GCD & LCM Distributive Law]
24656
Proving that $\frac{\csc\theta}{\cot\theta}-\frac{\cot\theta}{\csc\theta}=\tan\theta\sin\theta$
17264
Given $a,b,c$ are the sides of a triangle. Prove that $\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b}<2$
111815
Determine angle $x$ using only elementary geometry
130517
$ABCD$ is a square and $AEB$ is an equilateral triangle. Find $\angle DEC$.
29018
Do the BAC-CAB identity for triple vector product have some intepretation?
61343
Prove that if $\alpha, \beta, \gamma$ are angles in triangle, then $(tan(\frac{\alpha}{2}))^2+(tan(\frac{\beta}{2}))^2+(tan(\frac{\gamma}{2}))^2\geq1$
2251
Can someone give me a hint on how to prove this?
101476
If $A$, $B$ and $C$ are the angles of a triangle then find the value of $\Delta$
148934
Proof of Archimedes Principle
142835
Proving :$\arctan(1)+\arctan(2)+ \arctan(3)=\pi$
80789
Prove that $\forall a,b,c,d\in \mathbb{R}\,$, $(a^2-b^2)(c^2-d^2)\leq(ac-bd)^2$ and equalities hold if and only if $ad=bc$.
127380
Use vectors to prove $\cos(\beta - \alpha) = \cos \alpha \cos\beta + \sin\alpha \sin\beta$