In order to rationalise the fraction I must multiply the numerator and denominator by . I do not understand why this is so. Why does the sign only change for the surd and not the rational number (1) which is added to it?
In order to rationalise the fraction I must multiply the numerator and denominator by . I do not understand why this is so. Why does the sign only change for the surd and not the rational number (1) which is added to it?
So why does that identity help us rationalise that fraction?
For integers a and b with b non-negative, if you have denominator and you multiply it by you get which is an integer. Thus we have made the denominator rational.