Limit is multiplicative: Difference between revisions

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Suppose <math>f</math> and <math>g</math> are [[function]]s of one variable. Suppose <math>c \in \R</math> is such that both <math>f</math> and <math>g</math> are defined on the immediate left and the immediate right of <math>c</math>. Further, suppose that the [[fact about::limit]]s <math>\lim_{x \to c} f(x)</math> and <math>\lim_{x \to c} g(x)</math> both exist (as finite numbers). In that case, the limit of the [[fact about::pointwise product of functions]] <math>f \cdot g</math> exists and is the sum of the individual limits:
Suppose <math>f</math> and <math>g</math> are [[function]]s of one variable. Suppose <math>c \in \R</math> is such that both <math>f</math> and <math>g</math> are defined on the immediate left and the immediate right of <math>c</math>. Further, suppose that the [[fact about::limit]]s <math>\lim_{x \to c} f(x)</math> and <math>\lim_{x \to c} g(x)</math> both exist (as finite numbers). In that case, the limit of the [[fact about::pointwise product of functions]] <math>f \cdot g</math> exists and is the sum of the individual limits:


<math>\lim_{x \to c} (f \cdot g)(x) = \lim_{x \to c} f(x) \cdot \lim{x \to c} g(x)</math>
<math>\lim_{x \to c} (f \cdot g)(x) = \lim_{x \to c} f(x) \cdot \lim_{x \to c} g(x)</math>


Equivalenty:
Equivalenty:


<math>\lim_{x \to c}[f(x)g(x)] = \lim_{x \to c} f(x) \cdot \lim_{x \to c}g(x)</math>
<math>\lim_{x \to c}[f(x)g(x)] = \lim_{x \to c} f(x) \cdot \lim_{x \to c}g(x)</math>

Revision as of 01:41, 16 October 2011

Statement

Suppose f and g are functions of one variable. Suppose c∈R is such that both f and g are defined on the immediate left and the immediate right of c. Further, suppose that the limits limx→cf(x) and limx→cg(x) both exist (as finite numbers). In that case, the limit of the pointwise product of functions f⋅g exists and is the sum of the individual limits:

limx→c(f⋅g)(x)=limx→cf(x)⋅limx→cg(x)

Equivalenty:

limx→c[f(x)g(x)]=limx→cf(x)⋅limx→cg(x)