Why not 1/irrational? An older math teacher told me that I shouldn't leave a fraction with an irrational in the denominator. But lately, I keep hearing this from every math teacher that I have ever had.Thus if I have this fraction 1/(2^(1/2)) I should always convert it to one that has no irrationals in the denominator (2^(1/2))/(2) But why? My thought are that, just like the fact that we can't write out irrationals, we cant write fractions with irrational as denominators as decimals, but we can approximate them, so I don't see the problem. If we approximate 1/(sqrt 2) , it would be around 0.70710678118, so I dont understand why I shouldn't include irrationals in denominators, at least if I don't want some points deducted from a test.

zaiskaladu

zaiskaladu

Answered question

2022-09-20

Why not 1/irrational?
An older math teacher told me that I shouldn't leave a fraction with an irrational in the denominator. But lately, I keep hearing this from every math teacher that I have ever had.
Thus if I have this fraction
1 2 1 / 2
I should always convert it to one that has no irrationals in the denominator
2 1 / 2 2
But why? My thought are that, just like the fact that we can't write out irrationals, we cant write fractions with irrational as denominators as decimals, but we can approximate them, so I don't see the problem. If we approximate 1 / 2 , it would be around 0.70710678118, so I dont understand why I shouldn't include irrationals in denominators, at least if I don't want some points deducted from a test.

Answer & Explanation

embraci4i

embraci4i

Beginner2022-09-21Added 10 answers

If I want to compute 1 / 2 , I have to divide by 1.414, at first glance. Ick! 4-digit long division! But if I convert it to 2 / 2, I just have to divide by 2. Heck, I can do that in my head.
lunja55

lunja55

Beginner2022-09-22Added 1 answers

Much of it is a matter of aesthetics. The radical in the denominator is "ugly."
Part of it is just to teach people the algebra so that they know that they can move the radical around.
However, after you progress to a certain level you will quite frequently see 1 2
Regarding your example... 1 2 1 2 = 2 1 2 2 . If you are going to use the fractional notation, then you might as well say 2 1 2 . I think that is neater. Again it is matter of aesthetics.

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