Simple function give complex number

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boureghda mohammed 2016-12-24

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评论： Star Strider 2016-12-24

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Hi,

I have theses two function:

f1=-(x5 - x7^(1/a))/(T + T0)^2;
f2=(x8*(T*x5 + T0*x7^(1/a)))/(T0*x7*(T + T0)^2) - (x5*x8)/(T0*x7*(T + T0));

x5,x7,x8 are variables and a,T0,T are parameters.

When I run the code for a range of real values of variables and parameters, I always get a complex number for both functions, I do not know why this is happening.

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Star Strider 2016-12-24

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I suspect ‘x7’ is negative. If ‘a’ is not equal to 1, this will result in a complex result.

Example:

test = (-2)^(1/3)
test =
   629.9605e-003 +  1.0911e+000i

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boureghda mohammed 2016-12-24

thank you Star Strider.

Star Strider 2016-12-24

My pleasure.

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