Year 12s: what will be the first way you research your future options? >>

Surds Help

PersonInProgress

I have been struggling with this question and I can't find any help. Anyone know how to do it?

Photo on 19-06-2016 at 17.29 #2.jpg11.6KB

Reply 1

username1292215

Have you tried to rationalise the denominator :smile:

Reply 2

maccaism

times the denominator by 1-1/^2 and do the same w the top

Reply 3

PersonInProgress

Original post by maccaism

times the denominator by 1-1/^2 and do the same w the top

Why is it 1 - 1/root2 and not 1 + 1/root2?

Reply 4

PersonInProgress

Original post by SuperHuman98

Have you tried to rationalise the denominator :smile:

So I rationalised the 1/root 2 and then got 1/1+(root2/2) and then I simplified that to (4 + 2root2)/(4root2 +6) and then again simplifying it to (2 + root2) / (2root2 +3). That's where I got stuck.

Reply 5

maccaism

you do it so the surds cancel each other out :smile:

if you did a '+' then you'd have two times the surds whereas you want none

Reply 6

PersonInProgress

Original post by maccaism

you do it so the surds cancel each other out :smile:

if you did a '+' then you'd have two times the surds whereas you want none

Oh right. That makes sense. Ugh the one topic my maths teacher didn't teach us properly and it seems to come up a lot in the practise exams I'm doing.