+0  
 
0
112
3
avatar

if sqrt(2)*sqrt(8) = sqrt(2*8) why isnt sqrt(-1)*sqrt(-1)=sqrt(-1*-1)

Guest Apr 24, 2017
Sort: 

3+0 Answers

 #1
avatar+89827 
+1

 

if sqrt(2)*sqrt(8) = sqrt(2*8) why isnt sqrt(-1)*sqrt(-1)=sqrt(-1*-1)

 

\(if\;\; \sqrt2*\sqrt8= \sqrt{2*8}\\\text{ why isn't }\quad\\ \sqrt{-1}*\sqrt{-1}=\sqrt{-1*-1}\)

 

 

The rules for real numbers often do not extend to imaginary numbers. 

This is one such case.

 

Alan, or someone else might be able to give a better explanation.   :/

Melody  Apr 24, 2017
 #2
avatar
0

sqrt((-1)*(-1)) = +/-1

Guest Apr 24, 2017
 #3
avatar+75344 
+1

The rule is

 

√a  *  √b   =   √ [ a * b]   only if a, b  ≥  0

 

 

 

cool cool cool

CPhill  Apr 24, 2017

8 Online Users

avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details