2460673
contestada

When do you need to rationalize the denominator? My physics teacher says that you don't have to if you are isolating a variable.

Respuesta :

Answer:

When the denominator is an irrational number in order to make the denominator a rational number we rationalize the denominator.

Step-by-step explanation:

For example,

[tex]\frac{1}{1+\sqrt{2} }[/tex] (here the denominator is an irrational number)

Multiply the numerator and denominator by [tex]1-\sqrt{2}[/tex]

We get [tex]\frac{1-\sqrt{2} }{(1+\sqrt{2})(1-\sqrt{2}) }[/tex]

Here (1+\sqrt{2})(1-\sqrt{2}) = -1

Thus we get [tex]\sqrt{2} -1[/tex]

Here the denominator has become a rational number.

When we are isolating a variable we are only taking the required variables to one side thus it doesn't require rationalization.

[tex]a = \frac{x}{1+\sqrt{2} }[/tex]

Then we can say,

[tex]x = a(1+\sqrt{2})[/tex]

No rationalisation required