The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Multiplying a Matrix By a Scalar

Date: 08/27/98 at 17:35:58
From: Anyela Torres
Subject: Multiplication of matrix by scale

I need to know how to multiply a matrix by a scalar. Can you help me? 
It's very important.

Date: 08/27/98 at 18:17:24
From: Doctor Pat
Subject: Re: Multiplication of matrix by scale


First, I assume you know what a matrix is, and what a scaler is, but 
here's just a brief description. A matrix is a rectangular array of 
numbers, and a scaler is a number without units attached. 4 is a 
scaler, but 4 feet is not. 

When you multiply a scaler times a matrix, the result is a new matrix 
in which each element in it is equal to the old element in that 
position times the scaler. For example, let:
   |  3   5   |  
   |          |
   |  2   -1  |  

which is a 2x2 matrix, and let the scaler be 6. Then the product 
6 times A  will equal a new matrix:

   |  18    30  |
   |            |
   |  12    -6  |  
I hope that helps.  Thanks for the question.  

- Doctor Pat, The Math Forum
Check out our web site!   
Associated Topics:
High School Linear Algebra

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.