Math Genuises

[Ikerous]

I know a lot of the people on this forum seem to be rather good at math, so help me out.

A line with slope m passes through the point (0, 4) and has the equation y=mx + 4.

Write the distance d between the line and the point (3, 1) as a function of m.

The only variable in the distance equation can be m.

If you can figure this out, you're smarter than i am.

If it helps any, i can give you the answer.
Its in the back of the book. I just need to figure out how they got it.

 

[Platinum]

haha ... you're in algebra 2 ? im doin that shit .. .but i dont feel like doing it

 

[Ikerous]

No, im in calc. I dont know why were doing this :-/
Its hard though.
I think were doing it cuz the second part of the question is about derivatives. That part is easy though.

 

[lePobz]

You need help with your English too, by the looks of it.

I'm definately not a Maths genius, far from it ;( Sorry.

 

[Fat Tony!]

Easy peasy just subsitute the co-ordinate values into it.
1=3m +4
-3=3m
therefore m=-1

 

[gh0st]

Easy peasy just subsitute the co-ordinate values into it.
1=3m +4
-3=3m
therefore m=-1

you can use the other coordinate value as well

 

[JimmehH]

Aren't we looking for d in terms of m and not the value of m?

Edit: Working on it but it doesn't look pretty.

 

[Ikerous]

You have to come up with an equation to find the distance between the line and that point for any value of m...

the answer is:

d=3|x+1| / sqrt(m^2 + 1)

Now can anyone explain why?

 

[JimmehH]

There's a handy formula for finding the perpendicular distance from a point (h,k) to a line with equation ax + by + c = 0. It's (|ah + bk + c|)/sqrt(a^2 + b^2)

In this case h=3, k=1, a=m, b=-1,c=4 therefore the distance equals

(|(3*m) + (-1*1) + 4|)/sqrt(m^2 + 1)
simplifies to
(|3*m + 3|)/sqrt(m^2 + 1)
simplifies to
3|m+1|/sqrt(m^2 + 1)

 

[DeathMark]

I can get the co-ordiantes that the lines will intersect in terms of m but not the distance. Not because I couldn't but because i'm too lazy and I already did a whole page of working thinking this was going to be easy. There has to be a simpler way of doing it though that just treating the m's as you would if they were a number.

 

[Prince of China]

If only Archimedes was still alive and visiting these forums...

 

[DeathMark]

I knew there had to be a handy formula - there always is in maths but they forget to tell you it most of the time.

 

[Foxtrot]

There's a handy formula for finding the perpendicular distance from a point (h,k) to a line with equation ax + by + c = 0. It's (|ah + bk + c|)/sqrt(a^2 + b^2)

In this case h=3, k=1, a=m, b=-1,c=4 therefore the distance equals

(|(3*m) + (-1*1) + 4|)/sqrt(m^2 + 1)
simplifies to
(|3*m + 3|)/sqrt(m^2 + 1)
simplifies to
3|m+1|/sqrt(m^2 + 1)

Thank god math is so simple.

 

[Ikerous]

Jimmeh had it.
Plus i just found a site on it.
http://www.tpub.com/math2/8.htm

 

[JimmehH]

Jimmeh had it.
Plus i just found a site on it.
http://www.tpub.com/math2/8.htm

W00t for meh. I just remembered that the formula required was in my A-Level formula book. Even used it in the exam I think.

 

[Gorgon]

WOW this place full of nerds

 

[Eightball]

i like boobies

 

[DeathMark]

WOW this place full of nerds

i like boobies

The complete and utter retards on these forums seem to balance it out though.

 

[HatRabit]

The complete and utter retards on these forums seem to balance it out though.

eh?? was that comment indirectly directed at people like me...

Damn You Mildly Intelligent People!!!

 

[DeathMark]

Where did you come from? No it wasn't directed indirectly or directly at you because I'm not too sure I know who people like you are. Sorry if I inadvertantly offended you.

 

[HatRabit]

Where did you come from? No it wasn't directed indirectly or directly at you because I'm not too sure I know who people like you are. Sorry if I inadvertantly offended you.

it wasn’t a serious post I just felt like posting something random that made no sense in the context of the other designated posts that existed within this thread :cheers:

 

[DeathMark]

Mine wasn't serious either and I was thinking of flaming you for the sake of it but it's easier to just be democratic about things.

 

[Rupertvdb]

i got a B in AS maths and then it flew from my mind, you guys are on form.

 

[Foxtrot]

I failed a basic standards math test in Minnesota, but I still scored better than 76% of the school on the ASVAB test in the math section...