Linear Algebra and Its Applications · Problem 7.2.2

Computations with Matrices — Gilbert Strang

Mathematics · matrix-norm

Problem

Which ``famous'' inequality gives

\|(A+B)x\| \leq \|Ax\| + \|Bx\|

, and why does it follow from equation (5) that

\|A+B\| \leq \|A\| + \|B\|