Prove orthogonality of x and y
65075
norm (x+y)= norm(x-y) implies x is perpendicular to y.
10715
Orthogonal projection and two subspaces
145885
Linear transformation preserving orthogonality
138931
Show that $||x+y||\cdot||x-y||\le||x||^2+||y||^2$
7775
Show that $|x-y|\leq |x|+|y|$.
92291
$U_1, U_2, ..., U_k$ subspaces of linear space $X$ with same dimensions, prove $X=U_1\oplus V=U_2\oplus V=...=U_k\oplus V$
42606
Orthogonality for Binomial Coefficients
83970
Proof of an elementary property of Projection Operators
99221
Orthogonality lemma sine and cosine
120766
Prove ${y_n}$ is a basis for a Hilbert space $H$.
26801
Show that orthogonal matrices are diagonalizable
94077
Proof of linear independence of $e^{at}$
27901
Proving $\sum\limits_{i=1}^k | \langle x,v_i \rangle \langle y,v_i\rangle| \leq \|x\|\cdot \|y\|$
73807
Prove positive definiteness
97994
Orthogonality Relations Exercise, Brezis' Book Functional Analysis
114524
Proof Verification: the orthogonal complement of the column space is the left nullspace
84999
$\exp(A)$ is orthogonal iff $A$ is skew symmetric