Convert any number to positive. How?

Question

How to convert any number (negative or positive) into a positive number.. For example, my input can be 4545 or -4545, I need the out come to be positive value 4545.

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score 14 · Answer 1 · answered May 28 '11 at 07:08

14

With a calculator, you could make a number positive in one of two (simple) ways:

$\text{abs}(x)$
$\sqrt{(x^2)}$

The first one is recommended, but the second one will work as well as the square root function on most calculators returns the positive root. Squaring a real number always makes it positive, so taking the square root of a number squared returns the positive number.

answered May 28 '11 at 07:08

El'endia Starman

3,988

2

Yes, by all means use $\operatorname{abs}(x)$! You don't want to waste time squaring and taking roots (you'll also have to cope with imprecisions)... – t.b. May 28 '11 at 07:10
1

Precisely. The second option is a work-around only (like if your calculator doesn't have an absolute-value function). – El'endia Starman May 28 '11 at 07:12
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In textbooks, the first one is often written $\lvert x\rvert$. – FUZxxl May 28 '11 at 08:57
no, square root give two results: +/- – Serg Kryvonos May 30 '18 at 06:57
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@Sergei: to be pedantic, the square root symbol always means the principal square root, which is positive. – El'endia Starman May 30 '18 at 12:26
Thanks @El'endiaStarman for clarification. You helped me to see the difference between the symbol and ^(1/2) – Serg Kryvonos Jul 11 '18 at 08:57

score 12 · Accepted Answer · answered May 28 '11 at 07:01

12

You just have to simply multiply by $-1$. For example if you have a number $-a$ then multiply by $-1$ to get $-a \times -1 =a$. If the number is positive then multiply by $1$.

Or if you are aware of the Absolute Value, then take the absolute value of the number.

answered May 28 '11 at 07:01

2

This is the problem. I am getting the first value from an equation. I do not know it would be positive or negative. But I want it in positive. So I need to apply some equation on it if I am right. – Muneer May 28 '11 at 07:04
cool. Absolute Value is working. – Muneer May 28 '11 at 07:11

Convert any number to positive. How?

2 Answers2

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