MATLAB Answers

## matlab giving complex number when the expected answer is a real number?

Asked by Sei Him Cheong

### Sei Him Cheong (view profile)

on 24 May 2018
Latest activity Commented on by Stephen Cobeldick

### Stephen Cobeldick (view profile)

on 24 May 2018
Accepted Answer by Mischa Kim

### Mischa Kim (view profile)

matlab is giving me complex number when the expected answer is a real number? The code is the following:
A1 = -1;
A = A1^1.5
A = 0.0000 - 1.0000i
The answer should have been -1
A = -1^1.5
A = -1
Can anyone tell me why this is the case? It is giving a complex number when a variable is used.
Many thanks

#### 1 Comment

Stephen Cobeldick

### Stephen Cobeldick (view profile)

on 24 May 2018
"Can anyone tell me why this is the case?"
Because unary negation has a lower priority than the power operation. You can check this yourself:

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## 1 Answer

Answer by Mischa Kim

### Mischa Kim (view profile)

on 24 May 2018
Accepted Answer

Note:
>> (-1)^1.5
ans =
0.0000 - 1.0000i
which is not the same as
>> -1^1.5 % = -(1^1.5)
ans =
-1

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