math help

[don~g]

sorry in advance if this is the wrong forum. please direct me to the right one if it is not.

i'm taking a cnc milling tech course at our local CC. i've run into a formula in one of my books which i absolutely cannot resolve and i'm not getting help from my instructor.

can anyone show me a site, or write down a better way for me to understand this formula? i actually think it might be wrong in the book....maybe it's just written so weird i just don't get it. it has brought all my studying to a halt because everything else is predicated on it. i'm a little frustrated.

d = (xa-xt)2 + (ya-yt)2 ...... everything from the first parenthese on is under a division sign.

in the book they end up with an even number in the example(.20) and then apparently divide it by .2 and end up with .447...

i don't get it.

the actual hole size is 12.15 and measured position x12.40 and y11.80 with true position of 12.

what am i looking at wrong here?

[Eurisko]

Originally Posted by don~g ... d = (xa-xt)2 + (ya-yt)2 ...... everything from the first parenthese on is under a division sign.

That isn't a division sign. It's a radical. Take the square root.

Originally Posted by don~g ... in the book they end up with an even number in the example(.20) and then apparently divide it by .2 and end up with .447... the actual hole size is 12.15 and measured position x12.40 and y11.80 with true position of 12..

Okay, you've found the center of a circle to be ( X=12.4 , Y=11.8 ).
The true position of the circle should be ( x=12, y=12 ).

How far is your circle from the true position of (12,12) ?

I'll use ^2 to indicate taking the square of a number. For example , 3^2 = 9.

d = square root ((xa-xt) ^2 + (ya - yt)^ 2)
Now plug your values in:

d= square root ( (12.4-12)^2 + (11.8-12)^2 )
d= square root ( ( .4 ^2) + (-.2 ^2) )
d= square root ( .16 + .04 )
d = square root ( .2 )
d = .4472

[don~g]

oh man. you do not know how grateful I am. you've saved me such a ton of grief it's rediculous.

thank you so, so, so much.

[Eurisko]

You're welcome.

The CNC milling will be fun. More fun than the math

[ImanCarrot]

Eurisco got it in one.

You're basicaly finding the hypotenuse of a right angle triangle which is your [edit]distance from true position to actual position[/edit].

The xa-xt is one side of the triangle, the ya-yt is the other side. Square one, square the other, add these together and take the square root of that to get your hypotenuse (d).

Never trust text books, they all have typos. Even "Engineering Mathematics", my bible lol.

[Kiwi]

Originally Posted by ImanCarrot ........You're basicaly finding the hypotenuse of a right angle triangle which is your diameter................ Never trust text books, they all have typos.

Do you mean Diameter or Radius or is this just a distance?

[ImanCarrot]

Whoops, my bad, meant "distance" not "diameter". I'm making lenses and diameter was in my head. Never post before your first coffee

[Splint]

Don,

if ever you need further math help (or any type of help) I have found Yahoo Answers to be of great value, allthough I'm sure there's plenty of people here who can assist.

Splint