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# Rules for radicals [Solved!]

### My question

Is it true that the rules for radicals only apply to real numbers? Because \sqrt {-2}\times \sqrt {-18} is not equal to \sqrt{-2 \times -18}?

### Relevant page

3. Simplest Radical Form

### What I've done so far

Read over the page and done the examples.

X

Is it true that the rules for radicals only apply to real numbers? Because \sqrt {-2}\times \sqrt {-18} is not equal to \sqrt{-2 \times -18}?
Relevant page

What I've done so far

Read over the page and done the examples.

## Re: Rules for radicals

Hi Rika

Thanks for your mail.

Yes, you are right. Ex 2(a) and 2(b) at the bottom of this page
indicate what you are saying:

1. Basic Definitions of Complex Numbers

Regards

X

Hi Rika

Thanks for your mail.

Yes, you are right. Ex 2(a) and 2(b) at the bottom of this page
indicate what you are saying:

<a href="/complex-numbers/1-basic-definitions.php">1. Basic Definitions of Complex Numbers</a>

Regards

## Re: Rules for radicals

Hello Murray,
This discussion from last year. Should school text books not mention the restrictions when working with "laws of exponents"? For example,
(a^m)^n=a^(mn) only when a > 0 and m and n integer?
[(-1)^2]^(1/2) != (-1)^(2xx 1/2 )
as is mentioned in this book:
Everything Maths and Science
but I do not see it in most school textbooks?
regards
Rika

X

Hello Murray,
This discussion from last year. Should school text books not mention the restrictions when working with "laws of exponents"? For example,
(a^m)^n=a^(mn) only when a &gt; 0 and m and n integer?
[(-1)^2]^(1/2) != (-1)^(2xx 1/2 )
as is mentioned in this book:
<a href="http://www.everythingmaths.co.za/maths/grade-10/03-exponentials">Everything Maths and Science</a>
but I do not see it in most school textbooks?
regards
Rika

## Re: Rules for radicals

Hi Rika

Sorry - I thought I responded to this already, but realised I wanted to make sure IntMath stated the correct conditions. It didn't, but it does now in the summary on this page: Numbers

Thanks for alerting us to this.

Regards
Murray

X

Hi Rika

Sorry - I thought I responded to this already, but realised I wanted to make sure IntMath stated the correct conditions. It didn't, but it does now in the summary on this page: <a href="/numbers/4-powers-roots-radicals.php">Numbers</a>

Thanks for alerting us to this.

Regards
Murray