What is this equivalent to

Question

4/(5-13^(1/2)) equals....

Answer 1

4/(5-13^½)=4/(5-√13).

To express this in rationalised form, multiply top and bottom by (5+√13). This moves the radical into the numerator: 4(5+√13)/(25-13)=(20+4√13)/12=(5+√13)/3. This is the exact answer.

An approximate answer is 2.8685.