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{(-1)^0.5}^2 is considered as an error.

but why does (sqrt(-1))^2 equal -1?

and does it mean this equation {(-1)^0.5}^2={(-1)^2}^0.5 is not valid?

 Jan 11, 2016

Best Answer 

 #1
avatar+128707 
+10

{(-1)^0.5}^2={(-1)^2}^0.5

 

This isn't triue......remember that sqrt(-1)  is defined as " i "   →  i^2   = -1

 

So....using the order of operations on the left side results in :

 

[ i ] ^2   = -1

 

But, using the order of operations on the right results in :

 

[ 1 ] ^0.5   =  sqrt (1)   = 1

 

The problem lies in the way the order of operations are performed...... in the first instance, we are squaring a "complex" number, but in the second, we are taking the square root of a real number......

 

 

cool cool cool

 Jan 11, 2016
edited by CPhill  Jan 11, 2016
 #1
avatar+128707 
+10
Best Answer

{(-1)^0.5}^2={(-1)^2}^0.5

 

This isn't triue......remember that sqrt(-1)  is defined as " i "   →  i^2   = -1

 

So....using the order of operations on the left side results in :

 

[ i ] ^2   = -1

 

But, using the order of operations on the right results in :

 

[ 1 ] ^0.5   =  sqrt (1)   = 1

 

The problem lies in the way the order of operations are performed...... in the first instance, we are squaring a "complex" number, but in the second, we are taking the square root of a real number......

 

 

cool cool cool

CPhill Jan 11, 2016
edited by CPhill  Jan 11, 2016

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