Calculate the base of power function

Question

Given function:

 y=power(x, z)

Where y is the base x raised to the power of z.

In Java and many other language, there is function Math.pow() to calculate this.

My question is: how to calculate x, given y and z? Is there a standard library function for this?

Answer 1

This is done easily enough by remembering a mathematical law:

• x ^ab = (x ^a ) ^b

And now because z*(1/z)=1, the inverse of raising to the power z is raising to the power 1/z. So in your case

• x = y ^1/z

Once you've got your power() function, that's all you need.