Refactor calculate function and replace power operator with Math.pow

[shem8]

No description provided.

[wilcoapp]

Checking now.

[wilcoapp]

The implementation incorrectly uses a '**' operator, but the task does not state a specific method to use. The descriptions indicate that was was used was neither Math.pow() nor any explicit indication of using alternatives to the math library.

[wilcoapp]

Congratulations, the code correctly implements the 'pow' operation using Math.pow() which fulfills the requirement to add an exponential function to the calculator.