# Rationalizing the denominator

1. Jul 15, 2009

### cragar

1. The problem statement, all variables and given/known data

1/((i-s)^2)) how do i rationalize this , would i multpiy top and bottom by
(i+s)^2

2. Jul 15, 2009

### tiny-tim

(rationalize? anyway …)

Yup!

3. Jul 15, 2009

### cragar

k thank-you

4. Aug 21, 2009

### Unit

By the way, what is the proper term? (assuming "rationalize" is not)

5. Aug 21, 2009

### symbolipoint

"Rationalize" is the correct vocabulary for what you wanted.

6. Aug 21, 2009

### tiny-tim

Re: "Rationalizing"

Hi Unit! Hi symbolipoint!

Well, "rationalize" means to make rational, which this doesn't, neither in the English nor in the mathematical sense.

It actually puts a complex number into the standard x + iy form, so I'd prefer to say "put into standard form" …

however … now you raise the point, I see that http://hyperphysics.phy-astr.gsu.edu/hbase/cmplx2.html#c2 and others do say "rationalize" … I wonder why?

7. Aug 21, 2009

### Mentallic

But it's asking to rationalize the denominator which is achieved. The denominator becomes real, and possibly rational depending on the value of s.

8. Aug 21, 2009

### Дьявол

For ex. 1/i where i is complex number. By multiplying with i / i you get i / i2 = i / (-1), which makes the denominator real number (also rational) since I can write (-1) as (-1)/1 and the final equation would be i / (-1) / 1. Now the denominator is rational and I rationalize the equation.

Regards.