Difference between revisions of "Square root"
(I believe this is a bit better... what about the other stuff on this page?) |
|||
| Line 5: | Line 5: | ||
Negative numbers have square roots that lie outside the [[real number|real numbers]], and involve what are called [[imaginary number|imaginary numbers]], constructed via use the square root of -1, which is labelled ''i''. Thus, the square root of -9 is 3''i''. | Negative numbers have square roots that lie outside the [[real number|real numbers]], and involve what are called [[imaginary number|imaginary numbers]], constructed via use the square root of -1, which is labelled ''i''. Thus, the square root of -9 is 3''i''. | ||
| − | Technically, all numbers have two square roots, one positive and the other negative, since sqauring the negative number results in a positive number. Thus, sqr(9)=plus or minus 3, written +/-3; likewise <math>\sqrt | + | Technically, all numbers have two square roots, one positive and the other negative, since sqauring the negative number results in a positive number. Thus, sqr(9)=plus or minus 3, written +/-3; likewise <math>\sqrt{-9} = \pm3i</math>. |
The square root of a number can also be denoted as <math>X^{\frac{1}{2}}</math>, or ''X''^(1/2) if superscript is not available. This can readily be seen by the rule of adding powers when multiplying: ''X''<sup>1/2</sup> <math>*</math> ''X''<sup>1/2</sup> = ''X''<sup>1/2+1/2</sup> = ''X''<sup>1</sup> = ''X''. | The square root of a number can also be denoted as <math>X^{\frac{1}{2}}</math>, or ''X''^(1/2) if superscript is not available. This can readily be seen by the rule of adding powers when multiplying: ''X''<sup>1/2</sup> <math>*</math> ''X''<sup>1/2</sup> = ''X''<sup>1/2+1/2</sup> = ''X''<sup>1</sup> = ''X''. | ||
[[category:mathematics]] | [[category:mathematics]] | ||
Revision as of 21:30, April 12, 2007
The square root of a number X is the number that, multiplied by itself, results in X. The symbol for the square root of X is <math>\sqrt{X}</math>. Many computer languages and spreadsheet programs use "sqr(X)" or "sqrt(X)"to express this, as do people when mathematical symbols are not conveniently available.
Some square roots are relatively simple whole numbers, for example, 3 is the square root of 9. Others are less amenable to expression, such as the square root of 2 (1.414...), which has been proven to be an irrational number.
Negative numbers have square roots that lie outside the real numbers, and involve what are called imaginary numbers, constructed via use the square root of -1, which is labelled i. Thus, the square root of -9 is 3i.
Technically, all numbers have two square roots, one positive and the other negative, since sqauring the negative number results in a positive number. Thus, sqr(9)=plus or minus 3, written +/-3; likewise <math>\sqrt{-9} = \pm3i</math>.
The square root of a number can also be denoted as <math>X^{\frac{1}{2}}</math>, or X^(1/2) if superscript is not available. This can readily be seen by the rule of adding powers when multiplying: X1/2 <math>*</math> X1/2 = X1/2+1/2 = X1 = X.