Strange problem with fractional exponents

Dear all,

I’m getting a strange problem: if I compute 27^1/3 I get 9, but according to the rules of fractional exponents I should get 3. Instead, if I compute 27^(1/3), thus altering the MATLAB default operations priority, I get 3 (the correct value based on the rules of fractional exponents).

I would like to know why this happens in MATLAB. It is strange that applying the MATLAB default priority of operations would lead to produce wrong results.

Thank you in advance,

Josh

Answer 1

[Walter Roberson]

^ has higher priority than / does, so in the case of 27^1/3 it is being interpreted as (27^1)/3 which is 9.

Look at https://www.mathworks.com/help/matlab/matlab_prog/operator-precedence.html and notice that matrix division / is only #5 but matrix power ^ is #2

[Josh Shamir]

Thank you Walter!