Use of brackets while multiplying expression

E_d=2.6*(((1-alpha)/Ku)^ 1/3)*(Pe^(-2/3));

While using this expression answers comes out be -0.0065 but if 1/3 is taken in bracket the answer changes and result is shown in complex form. Please explain the backend calculation by MATLAB.

[Alan Stevens]

What are the values of the constants in the expression?

[BALPARTAP SINGH]

alpha = 0.1198

Ku = -0.173016419

Pe = 17808.22486

Answer 1

[Alan Stevens]

You have

E_d = 2.6*((1-alpha)/Ku)^1/3*Pe^(-2/3)

which only raises the bracketed term to the power 1, then divides the result by 3.

If you had

E_d = 2.6*((1-alpha)/Ku)^(1/3)*Pe^(-2/3)

you would be raising the bracketed term to the power 1/3, which would result in a complex number (because of the negative value of Ku).

[Stephen23]

Because matrix power has higher precedence than matrix division:

https://www.mathworks.com/help/matlab/matlab_prog/operator-precedence.html