mathematical symbol in the result

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Fadzli 2017-3-3

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评论： Walter Roberson 2017-3-3

Hi all,

I just run a program in Matlab and it gives a result of "5.6490e-006 +9.7844e-006i". I know what does it means by "5.6490e-006" but I'm not sure about "+9.7844e-006i", why there is "i" symbol at the back. Maybe this is more to mathematical definition but anyone can help? Thanks

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Answer 1

Walter Roberson 2017-3-3

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The i represents sqrt(-1), so your result was 5.6490e-006 + sqrt(-1) * 9.7844e-006

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Answer 2

Fadzli 2017-3-3

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Thanks Walter Roberson... I just used a simple mathematical equation; y=2*((3*x)/(4*1847*pi))^(1/3) with x is given, so any reason why the answer was in the "sqrt(-1)" form?

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Walter Roberson 2017-3-3

You have negative x values, leading to a negative value to the 1/3 power.

You might perhaps be expecting the real root, but when you use ^ the operation is defined in terms of log and exp, which leads to complex values for most roots of negative values. You can use nthroot

https://www.mathworks.com/help/matlab/ref/nthroot.html

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