Cov(X,Y) = f(Cov(X,Z), Cov(Y,Z)) ?
104847
Minimum covariance of 2 random variables given the covariance of each with a third random variable
102553
How to show that $f(z) = f(i)$
146719
Functional equation $f(r \cos \varphi)+f(r \sin \varphi)=f(r)$
103019
Find all functoins $f: \mathbb R \rightarrow \mathbb R$ such that $\forall x,y \in \mathbb R f(xy+f(x))=xf(y)+f(x)$
142028
If $\vec{a},\vec{b},\vec{c},\vec{d}$are unit vectors, $(\vec{a}\times\vec{b}).(\vec{c}\times\vec{d})=1$ and $\vec{a}.\vec{c}=\frac{1}{2}$,then
73047
Proving surjectivity of $\cos(z)$ and $\sin(z)$ and find all $z : \cos(z) \in \mathbb R$ and all $z: \sin(z) \in \mathbb R$
81973
Definition of $d (P (x ,y )dx)$
10444
If $\{x,\{x,y\}\} = \{z, \{z,t\}\}$, then must it be $x = z$ and $y = t$?
55420
How does the chain rule work for functions from vectors to vectors?
32856
Functional equations $f(x+y)= f(x) + f(y)$ and $f(xy)= f(x)f(y)$
121494
Invariance, covariance and symmetry
73367
On $E[E[Y|X]|X]= E[Y|X]$
127000
When does $V = \ker(f) \oplus \operatorname{im}(f)$?
35178
Covariance of order statistics (uniform case)
49240
$\forall x,y \in \mathbb{R}:\vert\cos x- \cos y\vert\leq\vert x-y\vert$
124742
P(A|C)=P(A|B)*P(B|C)?
128639
Homoskedasticity Assumption: Var(y|x)=Var(u|x)=constant?