/sci/ - Science & Math

[Anonymous No.3235654]

what do you get and how?

[Josef !!nUf2NflSAyw No.3235658]

The dimension of the area of both the pool and the gap is <span class="math">\mathrm{length}^2[/spoiler].
You're welcome.

[Anonymous No.3235664]

>>3235658
i'm solving it with a system of equations and i'm doing:

x^2 - y^2 = 21
4x - y = 24

and i get some rational numbers, but the book says x = 5, y = 2

[Anonymous No.3235670]

>>3235664
4x+2y not 4x-y

[EK !EKFQOBUFnQ No.3235672]

X^2 - y^2 = 21
4x + 2y = 24
2y = 24 - 4x
y = 12 - 2x
x^2 - (12-2x)^2 = 21
x = 5 or 11.
has to be 5 because 11 is retarded.
x = 5, y = 2

...you're welcome.

[None !/oddSpacew No.3235677]

>>3235664
huh?
where does 4x-y come from?

[EK !EKFQOBUFnQ No.3235685]

>>3235677
he did it wrong. he didnt account for the extra perimeter caused by cutting out the y^2 piece, he just removed off the top-side (y)

[None !/oddSpacew No.3235687]

>>3235685
Ah. That would explain it.

[Anonymous No.3235692]

isn't this like 14 year old stuff?

[EK !EKFQOBUFnQ No.3235697]

>>3235692
probably, but i don't really give a fuck. its easy enough for me to do, and it kept me entertained for a few minutes...

[None !/oddSpacew No.3235698]

>>3235692
Yep. This is /sci/though.

[None !/oddSpacew No.3235706]

>>3235697
This is probably relevant to your interests:
Projecteuler.net

[Anonymous No.3235711]

>>3235670
>>3235672

ugh i tried 4x+2y too
how
so (12 - 2x)^2 should be giving me 4x^2 - 48x + 144
then i subtract that from x^2 to get -3x^2 + 48x - 144 = 21
then i divide by -3 to get x^2 - 16x - 48 = -21
add 21 to both sides to get x^2 - 16x - 27 = 0
and then plug into the quadratic formula?

[None !/oddSpacew No.3235725]

>>3235711
you should get
<span class="math">x^{2}-y^{2}=21[/spoiler]
<span class="math">4x+2y=24[/spoiler]
and then be able to find some parallels without needing to bring the quadratic equation into it.

[Anonymous No.3235734]

>>3235711
>then i divide by -3 to get x^2 - 16x - 48 = -21
>-21

21/-3 =/= -21. Just btw.

[EK !EKFQOBUFnQ No.3235738]

>>3235711
...no

<span class="math"> x^2 - (12-2x)^2 = 21 [/spoiler]
<span class="math"> x^2 -144 +48x -4x^2 = 21 [/spoiler]
<span class="math"> -3x^2 +48x = 165 [/spoiler]
<span class="math"> 3x^2 -48x + 165 = 0 [/spoiler]
<span class="math"> (3x-15)(x-11) = 0 [/spoiler]
x = 5 or x = 11

disregard the 11.

pluf x = 5 into:
<span class="math"> 4x + 2y = 24 [/spoiler]
<span class="math"> 20 +2y = 24 [/spoiler]
<span class="math"> 2y = 4 [/spoiler]
<span class="math"> y = 2 [/spoiler]

[Anonymous No.3235740]

>>3235734
shit i meant that
i dont know why i cant get this, what the fuck

[EK !EKFQOBUFnQ No.3235742]

>>3235738
>pluf
*plug

[EK !EKFQOBUFnQ No.3235745]

>>3235706
thankyou. :)

[Anonymous No.3235752]

>>3235738
wow, i added the 21 in the wrong place

thank you
fuck
i am so mad right now
god fucking damnit

[EK !EKFQOBUFnQ No.3235755]

>>3235752
no problem.
:)