two shitty surd questions (givf help)

[Bugz]

Can't do these little fuckers and I am fed up to hell with losing my weekend trying to work things out from a teacher tht is a tosspot.

/ = square root and ---- = divison

rationalising the denominator:


a) /11
-----
/132


b) 2
--------
/11 - /5

 

[Bugz]

ffs

does no1 here take/did a-level maths? :/

 

[Rhana]

Can't do these little fuckers and I am fed up to hell with losing my weekend trying to work things out from a teacher tht is a tosspot.

/ = square root and ---- = divison

rationalising the denominator:


a) /11
-----
/132


b) 2
--------
/11 - /5

I havent done this math, but can it be

a) 0.289

b) 1.85

Can be dead wrong too....

 

[Jugvayne]

/3
-----
6

/11 + /5
---------
3

 

[Bugz]

Jug how'd u work out a)?

 

[leviathane]

2
--------
/11 - /5

x

/11+/5
---------
/11+/5


= should be pretty ez to work out from there (cound't do it on one line so edited it soz.

 

[Bugz]

b) 2 /11+/5
-------- x -------- = should be pretty ez to work out from there
/11 - /5 /11+/5

aye b) ended up being...

1 divided by 6 ( /22 + /10)

Still no idea how to work out b) though - Jeg got the right answer however.

Givf method.

 

[Bugz]

Heres a third one:

7/2
----
/8 - /7

 

[Jugvayne]

Okay, multiply top and bottom by /132, this gives you /1452 over 132

/1452 simplifies to 22 /3, so you have 22 /3 over 132. 22 over 132 simplifies to 1 over 6, so final answer in simplest terms is /3 over 6.

 

[Jugvayne]

third one is 28 + 7 /14

edit: I got that by multiplying top and bottom by (/8 + /7), which gives:

7 /2 (/8 + /7)
-------------
(/8 - /7) (/8 +/7)

= 28 + 7 /14
------------
8 - 7

= 28 + 7 /14

 

[Bugz]

Okay, multiply top and bottom by /132, this gives you /1452 over 132

/1452 simplifies to 22 /3, so you have 22 /3 over 132. 22 over 132 simplifies to 1 over 6, so final answer in simplest terms is /3 over 6.

I love u.

And givf method for third question cuz u got tht right too

p.s - rep also

 

[Jugvayne]

Heh, cheers for the rep if you don't understand any of that, feel free to PM me for further help

 

[Bugz]

third one is 28 + 7 /14

edit: I got that by multiplying top and bottom by (/8 + /7), which gives:

7 /2 (/8 + /7)
-------------
(/8 - /7) (/8 +/7)

= 28 + 7 /14
------------
8 - 7

= 28 + 7 /14

How'd u get 28 + 7/14 from 7/2 (/8 + /7)?

 

[Jugvayne]

7 /2 (/8 + /7) -if you do this term by term-

= 7 /2 x /8
= 7 /(2 x 8)
= 7 /16
= 7 x 4
= 28

next term:

= 7 /2 x /7
= 7 /(2 x 7)
= 7 /14

which cannot be simplified any further, so final answer is 28 + 7 /14

 

[Bugz]

7 /2 (/8 + /7) -if you do this term by term-

= 7 /2 x /8
= 7 /(2 x 8)
= 7 /16
= 7 x 4
= 28

next term:

= 7 /2 x /7
= 7 /(2 x 7)
= 7 /14

which cannot be simplified any further, so final answer is 28 + 7 /14

thank you so much

our teacher is pressing us on a-level course @ yr 10. It's ok for the people at the top of the class but i'm at the bottom so it isn't as easy for me :<

edit - last one i promise:

/13 - /7
--------
/13 + /7

 

[Jugvayne]

Wow, that is pretty harsh, have you even sat GCSE maths yet? I've just completed the entire A-level syllabus in one year at year 12, and thought I was being pressed heh

 

[Bugz]

Wow, that is pretty harsh, have you even sat GCSE maths yet? I've just completed the entire A-level syllabus in one year at year 12, and thought I was being pressed heh

I sat the Maths GCSE about 2 weeks ago. Wasn't bad.

Teacher is pressing us to get the A-level maths started asap.



/13 - /7
--------
/13 + /7

have any idea of the answer (plz include method :>)

 

[Jugvayne]

Sure. Whenever you have a surd question where the denominator is /x + /y, you must multiply top and bottom by the conjugate (/x - /y).

In this example:

(/13 - /7) (/13 - /7)
--------------------
(/13 + /7) (/13 - /7)

multiply out the brackets leaves you with:

13 - /91 - /91 + 7
--------------
13 + /91 - /91 - 7

collect the terms:

20 - 2 /91
----------
6

these can all be divided through by 2 so final answer is:

10 - /91
---------
3

 

[DocWolfe]

lol... I could do these at gcse? pretty sure these were on the paper I took.

 

[Bugz]

Sure. Whenever you have a surd question where the denominator is /x + /y, you must multiply top and bottom by the conjugate (/x - /y).

In this example:

(/13 - /7) (/13 - /7)
--------------------
(/13 + /7) (/13 - /7)

multiply out the brackets leaves you with:

13 - /91 - /91 + 7
--------------
13 + /91 - /91 - 7

collect the terms:

20 - 2 /91
----------
6

these can all be divided through by 2 so final answer is:

10 - /91
---------
3

Mega thanks.

That was the last question thx god

 

[Bugz]

lol... I could do these at gcse? pretty sure these were on the paper I took.

You probably got basic surds in the higher paper at the end.

I got them too.

However, they don't contain the idea of rationalising and the numbers they give you are often low and extremely easy to work with.

 

[Jugvayne]

lol... I could do these at gcse? pretty sure these were on the paper I took.

Yeah, I did them at GCSE too, and with rationalising denominators and stuff, but recently they changed the A level syllabus, it used to be you did Pure 1 - Pure 3 with 3 applied modules, whereas now you do Core 1 - Core 4 with two applied. Basically they took a module out, and replaced it with nothing except GCSE stuff, which is how Core 1 is. It's a bit sad really, but I guess necessary to make maths more accessible to people.

 

[DocWolfe]

Yeah, I did them at GCSE too, and with rationalising denominators and stuff, but recently they changed the A level syllabus, it used to be you did Pure 1 - Pure 3 with 3 applied modules, whereas now you do Core 1 - Core 4 with two applied. Basically they took a module out, and replaced it with nothing except GCSE stuff, which is how Core 1 is. It's a bit sad really, but I guess necessary to make maths more accessible to people.

I can remember doing one calculator paper and one without... its been 5 years and I cant remember much of it :x think I've killed my braincells with drinking.

 

[Bugz]

Yeah, I did them at GCSE too, and with rationalising denominators and stuff, but recently they changed the A level syllabus, it used to be you did Pure 1 - Pure 3 with 3 applied modules, whereas now you do Core 1 - Core 4 with two applied. Basically they took a module out, and replaced it with nothing except GCSE stuff, which is how Core 1 is. It's a bit sad really, but I guess necessary to make maths more accessible to people.

Well the q's were out of a Pure 1 Mathsmatics book :l

<confused>

 

[Jai13]

i did these for higher lvl GCSE maths and to rationlise the demoniter you just times by that over itself

 

[tris-]

i did this at a level about 5 months ago. ive totally forgotten it all already :/