The Origami Forum

I've just downloaded referencefinder, and it would help to have a topic on it just so that others can have a knowledge base when they start using it.

Please contribute!!

N-section of angles emenating from a corner.

replace n with the division you want, and x with the number of these divisions.

This is what you need to enter into your calculator:
tan (90/n*x)

Call this value a. Now, in Referencefinder, click on line, and enter in as follows:
x1:1 y1:a
x2:0 y2:0

Now you have a sequence of diagrams n-secting the bottom left corner!

WhiperPuffin wrote:replace n with the division you want, and x with the number of these divisions.
This is what you need to enter into your calculator:
tan (90/n*x)

What do you mean by "replace n with the division you want"? Does that mean the calculated angle of the division (ex 90/7=12.857142857142857142857142857143)?

And does the equation mean 90 divided by n multiplied by x?

Good point WhisperPuffin!

Yes, ftangdude, you would do tan(3*90/7). Remember, you usually don't want to find the 1/n mark, because then finding the others takes even more work. What you want to do is find the n-2, n-4, n-8, n-16, etc. mark. (Or likewise the 2, 4, 8, 16, etc. mark) This number is whatever the largest power of 2 below n is. For instance to divide into 13, find 5/13 or 8/13, to divide into 7 find 3/7 or 4/7. Then you can divide the 2, 4, 8, 16 etc. easily.

Oh. thanks Jared.
Just another question... what does "Tan" mean? I understand what I need to do for the equation, but, oh well. And also, once I multiply 12.8571 by 3, do I make the product (38.5714) into a decimal (0.3857)? It doesn't seem like it to me, because I tried that in Reference Finder, and it didn't work out.

Time to go back to school

http://en.wikipedia.org/wiki/Trigonometry

I'm only in grade 7... I have absolutely no idea how to do trigonometry.
Would "tan" be the side length of the square?

Tan is what you do in Mexico on Spring break!

Haha!
But seriously, how do I calculate the value "a", with respect to the Tangent?

qtrollip wrote:Tan is what you do in Mexico on Spring break!

Or at my school all year long

ftangdude, tan means tangent. It's a trigonometric function made by dividing the side of a right triangle opposite of an angle by the side adjacent to that angle (the other short side).

Also if you want to do 3/7 you do 3/7, don't expand it into a decimal.

I am incredibly confused... do you multiply the tangent by the the equation in the brackets (like in a distributive algebraic equation)?
If that is so, then the tangent for a 3/7 right triangle is 0.8100 of a square, and therefore, a=31.2428. But how would I put that value into ReferenceFinder? Any x or y values need to be <1...

No, you don't multiply the tangent. Tangent is a function. You'll learn about it in algebra, don't worry about it. The only pertinent part here is that if you type into your scientific calculator:

3/7 x 90 then hit tan
or if it's one of the nicer ones:
tan(3/7 x 90)

You can plug the resulting number into ReferenceFinder to find the spot you need.

Oh, I see. Thanks, Jared (I wonder how many times I've written that; you're such a helpful person )

EDIT: Well, I put in the equation, and it totals out to 1.2540. I put that into reference finder, and it didn't work... What should I do to make it work? Do I just use the .2540 as y1?

It looks like you put in 4/7 instead of 3/7. The problem is, with the specific scenario Jared gave, you need to use an angle less than 45º for it to work. Fortunately we're working on a square, and that's not very hard to do... just measure from the other side. Using 3/7, I got an answer of .7974, which fits into referencefinder much better.

I find that for side and angle divisions, it's simpler to use a Fujimoto approximation. It's just as accurate, and doesn't take a computer to figure out...

I'm in grade 7 too, and im pretty good at maths. Some of the mathematics used in refencefinder just blows my mind.