Math help
 

IS anyone here good at this stuff.

i have 3 questions to due. And was wondering if anyone could give me a hand.

1. A circle has x intercepts at A(1,0) and B(5,0) and its center lies on the line y = 4. Determine the equation of this circle?.

2. Find the points of intersection between the circle (x - 3)2+ (y-1)2 = 5 and the line y = 2x -2

3. Find the shortest distance between the point P(6,5) and the line 3x+4y=24.

any help would be awesome.

thank you.

i would say brown

Grade 12 stuff? I would do it for you if I had some paper in front of me. And it might involve some multi-variable vector calculus. But those questions are easy! C'mon now.

6.2

Hey man, some of us had a hard time with Grade 12 Calc. It's not as hard as driving a MKIII Supra though, I hear that's really hard ;)

i guess i shoudl probably brush up on that stuff for sept :\

#1.

you know that the coordinate of the middle is (x,4)

(x - h)^2 + (y - k)^2 = r^2

in this equation you know that h and k is the coordinate of the midpoint of the circle..



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

ok and you also know that on the circle exists coordinates (1,0)...and (5,0)
you need to plug in these 2 coordinates into the equation separately and you'll get 2 linear equatoins

(1 - h)^2 + (0 - 4)^2 = r^2
(5 - h)^2 + (0 - 4)^2 = r^2

subract these 2 equations from 1 another...

(1-h)^2 - (5-h)^2 = 0

(1-h)(1-h) - (5-h)(5-h) = 0

1-2h+h - (25-10h+h)=0

1-2h+h-25+10h-h=0

8h-24=0

h= 24/8 = 3

so u know the midpoint is (3,4)

ok so plug in this midpoint again back into your circle equation

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

and plug in (1,0) into this equation and solve for r.... (you can also plug in (5,0), or any other coordinate that exists on the circle)

(1 - 3)^2 + (0 - 4)^2 = r^2

4+16= r^2

r= sqrt(20)

final answer...
(x - 3)^2 + (y - 4)^2 = 20

thank you

You know,

After I graduated from post sec. I have never needed to find the equation of a circle who's center lies on the line y=4 and has intercepts of A(1,0) and B(5,0). It just hasn't come up.

Maybe if you became a rocket surgeon?

must be calculating the radius of the cross section of a rocket........

Likewise... about the only post secondary math I've ever used is Discrete (binary, logic) and Newton's method.

Now, some of our programmers do lots of "fun" math all the time, but they're not in the department I run.

Deep cut Christian :( But I guess I totally deserve it. Hahaha.

hey thanks for your help. it is greatly appreciated.

I use simple trig all the time. But I wouldn't have a clue how to do this. Maybe if I really sat down and looked at it for an hour with paper and a calculator.

WingHang +1 respect

mathamacation is the proper word for every thing when it comes to this type of stuff

lol couldn't find help in the Vancouver Board, had to come here? :haha:

Less chance someone here would rat on him for cheating?

As you may be able to tell, I am not a fan of someone posting their school work to get someone else to do it.

This thread was started before the one on the Van side.