Question 753780
What do you mean?

The process depends on which expression you really have.  What you want simplified must be stated clearly.

Which of these is what you have as given?
'
{{{sqrt(1)+(4/5)/2}}}
'
{{{sqrt(1+4)/(5/2)}}}
'
{{{sqrt((1+4)/5)/2}}}
'
{{{sqrt((1+4/5)/2)}}}  -----------this one was wanted-----



Starting from here:
{{{sqrt((1+4/5)/2)}}}
You could begin by simplifying the complex fraction.
{{{(1+4/5)/2=1/2+4/(2*5)=(5/5)(1/2)+4/(2*5)=5/(2*5)+4/(2*5)=9/10}}}, just the simplification of the complex fraction.
So what you have, partly simplified, is {{{sqrt(9/10)}}}.


You want to now rationalize the denominator so watch this:

{{{sqrt(9/10)*(sqrt(10)/sqrt(10))}}}


{{{sqrt(9*10)/10}}}


{{{highlight(3*sqrt(10)/10)}}}