- #1

- 11

- 0

Rational / Irrational → Irrational / Rational

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- #1

- 11

- 0

Rational / Irrational → Irrational / Rational

- #2

- 11

- 0

Say for example,

- #3

Mark44

Mentor

- 34,819

- 6,565

The main rationale behind this technique is that it's easier to divide an irrational number by a rational number than the other way around, especially if you don't have a calculator or computer to do the work for you.

Rational / Irrational → Irrational / Rational

The technique is also used for fractions that involve complex numbers. For example, ##\frac 1 i## can be simplified by multiplying by the complex conjugate over itself; i.e., by multiplying by ##\frac{-i}{-i}## (which is 1). So ##\frac 1 i = \frac 1 i \cdot \frac{-i}{-i} = \frac{-i}{1} = -i##.

- #4

- 11

- 0

Thanks, and a small side question: How do you create the fractions? (on this forum)

- #5

jedishrfu

Mentor

- 12,642

- 6,498

https://www.physicsforums.com/help/latexhelp/

There's a simple example of the quadratic formula that has a fraction in it.

- #6

FactChecker

Science Advisor

Gold Member

- 6,175

- 2,387

[tex]\frac 1 i = \frac 1 i \cdot \frac{-i}{-i} = \frac{-i}{1} = -i[/tex]

- #7

Mark44

Mentor

- 34,819

- 6,565

I never use these any more -- I find it simpler to use $$ at the beginning of the expression and $$ at the end -- it's less to type. For stuff that I want to show inline, I use ## at the beginning and two more of them at the end. The ## pairs are equivalent to [itex] ... [/itex].FactChecker said:Copy it and surround it with [ tex] ... [/tex].

- #8

pwsnafu

Science Advisor

- 1,080

- 85

Share:

- Replies
- 5

- Views
- 759