2x Maths Questions (1 Viewer)

[Varin9]

Simutaneous Equations
Find real numbers for p,q,r-

p^2 + q^2 + r^2 = 3
p + q + r =1
p + 2q - r = 5

(just a thought, but i you square each term in the second one, it doesnt seem to work)

Solve for x and y

x + y * root2
------------- = root2
root2 - 1

Thanks in advance to everyone appreciate it

 

[Alkanes]

umm is the answer for the second question x = 2 and y = -1? ill post up the solution if its right =)

 

[SpiralFlex]

Disregard question fixing it soon

Let's add equation 2 and 3

p + q + r + p + 2q - r = 1 + 5

2p + 3q = 6 [Equation 4]

Now, let's minus equation 3 from 2

p + q + r - (p + 2q - r) = -4 Equation 5

-q + 2r = -4 [6]

Let's focus on equation [4] and [6]

2p + 3q = 6

- q + 2r = 4

Let's times [6] by 3

-3q + 6r = -12 [7]

[4] + [7]

2p + 6r = -6

Hence, p + 2r = -3

Change the subject for 2r: 2r = -3 - p [8]

Substitute this into equation [6]

-q + 2(-3-p) = -4

-q - 6 - 2p = -4

-q - 2p = 2 [9]

[4] + [9]

2q = 8

q = 4

Sub for the rest: you should get q = 1, p =

To be completed soon

Give me a second to finish this.

2nd one: times all sides by root 2.

2 - sqrt(2) = x + y sqrt 2

By the theorem of surds, x must be 2, y = -1 no matter what.

 

[Varin9]

回复: Re: 2x Maths Questions

Still working on first one.

2nd one: times all sides by root 2.

2 - sqrt(2) = x + y sqrt 2

By the theorem of surds, x must be 2, y = -1 no matter what.

Yeah i though that, thx, but the one that has me stumped is the first one.

 

[SpiralFlex]

Re: 回复: Re: 2x Maths Questions

Hold on mate, i'm trying to do it, it's taking long.

 

[jyu]

p^2 + q^2 + r^2 = 3
p + q + r =1
p + 2q - r = 5

Please check the equations

 

[SpiralFlex]

Mmm, give me a few more minutes.

 

[jyu]

your time is up

 

[AAEldar]

Just solved it.



Or



Will post working up in a sec.

 

[SpiralFlex]

Correcting my answer.

 

[ohexploitable]

or

 

[jyu]

Just solved it.



Or



Will post working up in a sec.

don't satisfy the first eqn

 

[ohexploitable]

Please check the equations

There's nothing wrong with them, my posted solution works.

 

[AAEldar]

don't satisfy the first eqn

Lololol I completely forgot about the first equation.

Well that's lame. It seemed so nice

 

[820]

There's nothing wrong with them, my posted solution works.

op says real numbers

 

[SpiralFlex]

I thought it was real numbers.

 

[jyu]

or

i think real solutions are required?

 

[ohexploitable]

There are no real solutions then.

 

[AAEldar]

Question lies then? D:

 

[SpiralFlex]

I'm sure I have seen this in one of the Cambridge books. Can you check if you typed equations right?