Define $\triangle$ as $A\triangle B = (A\cup B - A\cap B )$, show associativity of $\triangle$
12459
Associativity of symmetric difference of sets
216
In a $\triangle ABC,a^2+b^2+c^2=ac+ab\sqrt3$,then the triangle is
101803
A\(B∩C) = (A\B) ∪ (A\C) how to prove?
52323
Maps - question about $f(A \cup B)=f(A) \cup f(B)$ and $ f(A \cap B)=f(A) \cap f(B)$
75604
Proof that $\partial(A\times B) = ((\partial A)\times B)\cup (A\times(\partial B))$
2208
$\gcd(a,b,c)=\gcd(\gcd(a,b),c)\,$ [GCD Associative Law]
123890
Show $A\setminus (A\cap B)=(A\cup B)\setminus B$
75017
Definition of General Associativity for binary operations
130513
LCM is associative: $\ \text{lcm}(\text{lcm}(a,b),c)=\text{lcm}(a,\text{lcm}(b,c))$
60707
Show that if $ \ A \cup B = A$ and $ \ A\cap B = A$ then $ \ A = B$
106564
Suppose $A,B,C$ are sets. Prove that $A\mathbin\triangle B\subseteq C \iff A\cup C=B\cup C$.
76188
Show $(W_1 + W_2 )^\perp = W_1^\perp \cap W_2^\perp$ and $W_1^\perp + W_2^\perp ⊆ (W_1 \cap W_2 )^\perp$
68869
How to show that the triangle is equilateral triangle?
38200
Show that $(\mathbf{a}·\mathbf{a})(\mathbf{b}·\mathbf{b})-(\mathbf{a}·\mathbf{b})^2=(\mathbf{a}\times\mathbf{b})·(\mathbf{a}\times\mathbf{b})$?
50266
In the following figure prove that: $AK||BC$
144360
For any sets $A$ and $B$, show that $(B\smallsetminus A)\cup A=B \iff A\subseteq B$.
13415
How to show if $A \subseteq B$, then $A \cap B = A$?