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classified 01-17-2009 09:03 PM

Quote:

Originally Posted by T.H.C (Post 6230189)
no, its 5!

going back in time i realised i carried the 13 wrong. you are correct

Dr-Vn 01-17-2009 09:07 PM

http://3.bp.blogspot.com/_cPczfwigsP...hPendaison.jpg
http://static.pyzam.com/img/funnypics/misc/test3.jpg

alex.w *// 01-17-2009 09:14 PM

lol i remember ppl asking this on vancouver xchange, under the school subforum.

they actually got help cuz probably 90% of the members there were highschoolers

sas 01-17-2009 09:30 PM

I won't do it for you, but..

determine your centre for your circle. H, K

Use the standard or general formula, maybe midpoint forumula since your given 4 points, etc.. (its been a long time) (x-h) + (y-k) = r

chouchou 01-17-2009 09:32 PM

Quote:

Originally Posted by CruisingDream (Post 6229720)
this is like gr 12 math? pretty easy stuff man

grade 10 :P
hahaha

Adrenaline Rush 01-17-2009 09:43 PM

http://www.enzine.cyborgcow.net/exam/010.jpg

viper11885 01-17-2009 09:49 PM

Quote:

Originally Posted by HB20 (Post 6229741)


I've seen the others in this thread. But this one is new to me :rofl::rofl::rofl:

wuuhoo 01-17-2009 10:18 PM

lmao

!Aznboi128 01-17-2009 10:42 PM

http://www.funnyandjokes.com/wp-cont...y-is-wrong.jpg

Gary Oak 01-18-2009 12:45 AM

ahaha dont do it...
your never gonna use this in life

twitchyzero 01-18-2009 12:56 AM

yeah math 12 stuff...it's one of the easiest chapter.

Math 11 was so much harder than math 12 i thought.

for the OP..i suggest getting the "Byng book" of old provincial exams..it sorts out a lot of old exam Q by its section. If it wasnt for that book, I wouldn't be in university right now hahah

tamiya_s2000 01-18-2009 01:38 AM

zomg rocket science!!!!
lol lazy shit.. answers are:
1. 6
2. (F4,1L)
3. 3.2km

Quote:

Originally Posted by HB20 (Post 6229741)

lol nice

cctw 01-18-2009 01:52 AM

i'll teach..$30/hr lol =)

slammer111 01-18-2009 02:14 AM

Since nobody's helping, ah what the hell, I'm bored. :) No guarantees on the accuracy, but here goes. Damn I miss doing this stuff.

Just wondering, what grade Math is this?

Not gonna show the full work (how do you type equations lol), but here are the solutions.

1. Make a centre point C(h,4). By eyeballing it or drawing it on grid paper (and yes you can prove it using Pythogoras as well), you'll find that h = 3, so C(3,4) is the centre. Use Pythagoras again, and you'll find R^2 = 13. Stick that into General Form. h = 3, k = 4, R^2 = 13.
2. Since you know y = 2x - 2, substitute that into "y" in your circle equation to get 5x^2 - 18x + 13 = 0. Solve the quadratic and you'll get x1 = 2.6, x2 = 1. Plug into line (or circle if you want but line's way easier) equation to get intersection points P1(2.6,3.2) and P2(2,0).

3. Change the line to General Form y = mx + b, or y = (-3/4)x + 6. Find the line (with slope m2) that's perpendicular between the existing line (which has slope m1 = -0.75). Remember that perpendicular lines have slopes m1 * m2 = -1, therefore m2 = 4/3. Plug coordinates of P into the equation, so 5 = (4/3)(6) + b, so b = -3. Now find the intersection points of these 2 lines y = (4/3)x - 3, y = (-3/4)x + 6. Solve to find intersection point A(102/25,69/25) or A(4.32,2.76). Then use Pythagoras to get the distance between A and P, d = 2.8.

noots 01-18-2009 02:31 AM

Quote:

Originally Posted by slammer111 (Post 6230642)
Since nobody's helping, ah what the hell, I'm bored. :) No guarantees on the accuracy, but here goes. Damn I miss doing this stuff.

Just wondering, what grade Math is this?

Not gonna show the full work (how do you type equations lol), but here are the solutions.

1. Make a centre point C(h,4). By eyeballing it or drawing it on grid paper (and yes you can prove it using Pythogoras as well), you'll find that h = 3, so C(3,4) is the centre. Use Pythagoras again, and you'll find R^2 = 13. Stick that into General Form. h = 3, k = 4, R^2 = 13.
2. Since you know y = 2x - 2, substitute that into "y" in your circle equation to get 5x^2 - 18x + 13 = 0. Solve the quadratic and you'll get x1 = 2.6, x2 = 1. Plug into line (or circle if you want but line's way easier) equation to get intersection points P1(2.6,3.2) and P2(2,0).

3. Change the line to General Form y = mx + b, or y = (-3/4)x + 6. Find the line (with slope m2) that's perpendicular between the existing line (which has slope m1 = -0.75). Remember that perpendicular lines have slopes m1 * m2 = -1, therefore m2 = 4/3. Plug coordinates of P into the equation, so 5 = (4/3)(6) + b, so b = -3. Now find the intersection points of these 2 lines y = (4/3)x - 3, y = (-3/4)x + 6. Solve to find intersection point A(102/25,69/25) or A(4.32,2.76). Then use Pythagoras to get the distance between A and P, d = 2.8.

what he said

chouchou 01-18-2009 02:48 AM

^damn ninja'd.. i knew that..:P

cctw 01-18-2009 03:11 AM

Quote:

Originally Posted by slammer111 (Post 6230642)
Since nobody's helping, ah what the hell, I'm bored. :) No guarantees on the accuracy, but here goes. Damn I miss doing this stuff.

Just wondering, what grade Math is this?

Not gonna show the full work (how do you type equations lol), but here are the solutions.

1. Make a centre point C(h,4). By eyeballing it or drawing it on grid paper (and yes you can prove it using Pythogoras as well), you'll find that h = 3, so C(3,4) is the centre. Use Pythagoras again, and you'll find R^2 = 13. Stick that into General Form. h = 3, k = 4, R^2 = 13.
2. Since you know y = 2x - 2, substitute that into "y" in your circle equation to get 5x^2 - 18x + 13 = 0. Solve the quadratic and you'll get x1 = 2.6, x2 = 1. Plug into line (or circle if you want but line's way easier) equation to get intersection points P1(2.6,3.2) and P2(2,0).

3. Change the line to General Form y = mx + b, or y = (-3/4)x + 6. Find the line (with slope m2) that's perpendicular between the existing line (which has slope m1 = -0.75). Remember that perpendicular lines have slopes m1 * m2 = -1, therefore m2 = 4/3. Plug coordinates of P into the equation, so 5 = (4/3)(6) + b, so b = -3. Now find the intersection points of these 2 lines y = (4/3)x - 3, y = (-3/4)x + 6. Solve to find intersection point A(102/25,69/25) or A(4.32,2.76). Then use Pythagoras to get the distance between A and P, d = 2.8.

i'm bored so i'll make corrections...
#1: R^2 = 20 not 13..just plug one of the coordinates back into your equation (x-3)^2 + (y-4)^2 = R^2 and you'll see

#2: its P2(1,0)..

#3: its A(108/25, 69/25)..decimal answers are correct though

StaxBundlez 01-18-2009 04:18 AM

hahhahahahahah revscene... no help at all

slammer111 01-18-2009 05:18 AM

Quote:

Originally Posted by cctw (Post 6230674)
i'm bored so i'll make corrections...
#1: R^2 = 20 not 13..just plug one of the coordinates back into your equation (x-3)^2 + (y-4)^2 = R^2 and you'll see

#2: its P2(1,0)..

#3: its A(108/25, 69/25)..decimal answers are correct though

Good call. Yeah I checked, and you're right on all 3 corrections :) Oh well, hopefully the OP gets the gist of it at least.

J-Wangsta 01-18-2009 12:08 PM

hey! its pretty foggy out there eh?

no_mercy 01-18-2009 03:02 PM

so in addition to the answers above

#1. since you know (h,4)
the equation of a circle must be (x+h)^2 + (y-4)^2 = r^2
now plug in your first coordinates (x=1, y=0) into the equation of the circle you'll get

(1+h)^2 + (0-4)^2 = r^2
h^2+2h+1+16 = r^2
h^2+2h+17=r^2 <--- equation A

now plug in your second coordinates (x=5, y=0) into the equation of the circle and you'll get
(5+h)^2+(0-4)^2 = r^2
h^2+10h+25+16 = r^2
h^2+10h+41 = r^2 <---- equation B

Since you know that those two coordinates lie on the circle, their radius must be the same so you can equate the two equations together and eliminate variables OR set them up in a linear system and reduce it (linear algebra)

h^2+2h+17=r^2 <--- equation A
h^2+10h+41 = r^2 <---- equation B

so setting the radius equal to each other of equation A and equation B (A=B) we get

h^2+2h+17 = h^2+10h+41
2h+17=10h+41
-24=8h
h=-3

Now you can plug the h back into the equation of a circle

(x-3)^2 + (y-4)^2 = r^2

Your centre is (3,4) describe in the equation and your radius is unknown but that is easy since you have an X and Y coordinate of your choice (x=1,y=0) or (x=5,y=0)
plugging those numbers in you'll find that r^2 = 20

sIN 01-18-2009 04:36 PM

thank you very much. \I would not be able to do this with out the help


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