Math Is Fun Forum

im really bored

Member

Registered: 2005-05-12

Posts: 76

Last one hopefully

Find the square root of (3/2)(x-1) + (sqrt(2x^2 - 7x - 4))

its not equal to anything so its all about manipulation, thats about all I can help lol.

Zach

Member

Registered: 2005-03-23

Posts: 2,075

Re: Last one hopefully

I don't suppose you could express that in better terms?

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Boy let me tell you what:
I bet you didn't know it, but I'm a fiddle player too.
And if you'd care to take a dare, I'll make a bet with you.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Last one hopefully

This is as far as I can get:

(3/2)(x-1) + sqrt(2x^2 - 7x - 4))

(3/2)(x-1) + sqrt(2x^2 - 8x + x - 4))

(3/2)(x-1) + sqrt(2x(x-4) + x - 4))

(3/2)(x-1) + sqrt((2x+1)(x-4))

(3/2)(x-1) + sqrt(2x+1)*sqrt(x-4)    (best I can do)

Try squaring:

[(3/2)(x-1)]^2 + 2 * (3/2)(x-1) * sqrt(2x+1)*sqrt(x-4) + (2x+1)*(x-4)

9/4 * (x-1)^2 + 3 * (x-1) * sqrt(2x+1)*sqrt(x-4) + (2x+1)*(x-4)

Nope, didn't do any good. Ah well ....

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

im really bored

Member

Registered: 2005-05-12

Posts: 76

Re: Last one hopefully

Im not having any better luck with this problem

scobbysteve

Member

Registered: 2005-05-17

Posts: 1

Re: Last one hopefully

i hate maths if hitler was maths, wed all be dead by now

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Last one hopefully

In other words ... Hitler/Maths would have had the power to defeat the Allies, and then would have gone on to kill everyone he now successfully ruled?

This is a new theory I hadn't encountered before.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Vulcan

Member

Registered: 2005-04-23

Posts: 224

Re: Last one hopefully

?!?!?!

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one day, i couldn't find my hat
then it occured to me that i didn't have one
so i didn't where it!!!

im really bored

Member

Registered: 2005-05-12

Posts: 76

Re: Last one hopefully

So does anyone have any idea on how to do this problem?

Zach

Member

Registered: 2005-03-23

Posts: 2,075

Re: Last one hopefully

Hitler wasn't going to kill everyone he ruled.

---

Boy let me tell you what:
I bet you didn't know it, but I'm a fiddle player too.
And if you'd care to take a dare, I'll make a bet with you.

complaint

Guest

Re: Last one hopefully

Zach got rid of his animal thingy!

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Last one hopefully

He did ... I don't know what he replaced it with either.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Roraborealis

Member

Registered: 2005-03-17

Posts: 1,594

Re: Last one hopefully

A ferret reaper.

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School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

stewie

Member

Registered: 2005-03-28

Posts: 820

Re: Last one hopefully

I have 2 admit it looks a lot better - good work zach *throws up*

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Zach

Member

Registered: 2005-03-23

Posts: 2,075

Re: Last one hopefully

Silence yourself, Stewie. My Ferret Reaper will destroy you!

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Boy let me tell you what:
I bet you didn't know it, but I'm a fiddle player too.
And if you'd care to take a dare, I'll make a bet with you.

im really bored

Member

Registered: 2005-05-12

Posts: 76

Re: Last one hopefully

well anyways back to my original question,     I got some help from a friend and they said to start by making the (3/2)(x-1) into one term, and then multiply the sqrt by something that will allow you to combine it with the expanded fraction, then go from there. And they said that the final solution will end up with a square root inside of a square root, and that there wasnt a way that they knew to get around it.

Roraborealis

Member

Registered: 2005-03-17

Posts: 1,594

Re: Last one hopefully

Then, we'll first need to multiply out the brackets.
Is that 3/2 a three divided by 2?

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School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

im really bored

Member

Registered: 2005-05-12

Posts: 76

Re: Last one hopefully

Yes it is a 3 divided by a 2.   Now after following some of their advice I combined both terms to make one term which is:     (3x - 3)    +    (sqrt(2x^2 - 7x - 4))   All divided by 2.  But I can't get any further at the moment

cool_me

Member

Registered: 2005-05-26

Posts: 11

Re: Last one hopefully

hey who ever u r  i got the answer for u.telling u something tht go order wise and get ur answer.
the no not possibly will be a perfect sqr. so u can actaually do it calmly!ur answer + question is toooo difficult.
the answer by me is not valid.
NO VALUE.
COZ,
3/2 x -1 + sqrt of (2^2 -7 x -4)
=-3/2 + sqrt of 12

sqrt of 12 does not come in whole nos. u cant add approximation
( if u do it this way)

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Last one hopefully

cool_me, you are genius ...

... I think

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman