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#scalarproductnorm#scalarproduct#triangleinequality#cauchyschwarz

Unit 1 · 8.1 · Vectors, norms & sequences

Scalar product & Euclidean norm

The scalar product combines two vectors into a number; the Euclidean norm measures length. The triangle and Cauchy–Schwarz inequalities are the two estimates everything later relies on.

Unit 1 · 8.1
Formulas at a glance · Vectors, norms & sequences

Scalar product & Euclidean norm

u⋅v=∑i=1nuivi,‖v‖2=v⋅v,|u⋅v|≤‖u‖2‖v‖2

Norms & unit balls

‖v‖∞≤‖v‖2≤d‖v‖∞,1d‖v‖1≤‖v‖2≤‖v‖1

Sequences in ℝᵈ

xk→y⟺‖xk−y‖2→0