Math question
 

Ok, so I am refreshing myself with some math. I am going over Slope-Intercept Form of a line

y=mx+b

and,

"point-slope" form of the equation

Is this the same thing? I guess not.

And then you have General Form, Ax + By + C = 0
What's the C? It seems to be missing from the other formulas :O: As well as the A & B?

Just reading that gave me the same mind-numbing, out-of-body feeling I used to get in high school...

Thanks for the cheap high, Neal... :D

(Oh, and if I remember correctly, the answer is always "B"...)

...

They are the same. *Just solve for y.

Ax + By +C = 0

Becomes

y = -(A/B)x -(C/B)

So in y=mx+b

m = -(A/B)
And
b= -(C/B)

(note upper/lower case)

use wolfram alpha (http://worlframalpha.com)

it is a math student's best friend

Except for when I'm trying to use it to estimate the cost of welding jobs. When I ask for the mass of given volume of steel, it gives me the price of steel futures. Wtf ?

It wont help him learn how the equation works either.

How did it become that second line?


Ax + By +C = 0

Subtract C from both sides:
Ax + By = -C

Subtract Ax from both sides:
By = -C -Ax

Divide both sides by B:
y = (-C -Ax)/B

How does it become:
y = -(A/B)x -(C/B) ??

I have been watching instructional videos which are great except often the person who KNOWS how to do this forgets the pupil does NOT and assumes he does. :dead:

For example, I'm following along and then at :46 mark, bang! Where did out friends A, B, and C disappear to?? :o

Ax+By+C=0 then
By= -Ax-C and then
y=-(Ax/B)-(C/B)
-(Ax/B) is just the same as -(A/B)x
and here we have:
y=-(A/B)x-(C/B)
I hope this solve your dilemma Neal.

Yes, thanks, I just have to do about 300 examples to imprint it in my brain.

I learned this stuff about 4 times in my life... but it never gets used.

I want the 90 seconds back that it took me to read this!

My brain hurts now... HOPE YOUR HAPPY!

I saw Math Question and STILL clicked on the topic!!
:nope:

My head hurts!!
:doh:

Coincidentally, I just watch this:

http://tauday.com/

Makes sense.

Hey Neal,

Both:
http://www.khanacademy.org/#browse
http://patrickjmt.com/

are fantastic resources. Made my courses much more bearable for me.

PD

Do not seek the treasure!
:haha:

Bah

Math is fun. Dunno what you guys are crying about. :D

I'm crying because it hurts just to look at it.

My older daughter is a math genius. I'm a math idiot. I can never figure out manual targetting. I'm real good with simple arithmetic, but as soon as there are letters involved I'm lost. This is funny because I'm pretty good at letters too. I guess it's like politics and religion - numbers and letters don't mix for me.