n_ick2000

8th October 2001 00:30 UTC

Sin, Cos, Tan
I learned in my geometry class that sine, cosine, and tangent were triangle angle ratios. Exactly how do sin, cos, and tan effect superscopes and movements. I heard something about triangle angle ratios being in degress and superscopes and movements being in rads, but I don't know what that means. Can somebody please explain this to me?

Scarface2k1

8th October 2001 16:30 UTC

well,
i find that this will do fine for movement:

y=cos(t+i);

UnConeD

9th October 2001 23:38 UTC

Trigonometry :)
The easiest way to explain is this:

Given a circle with radius 1 (the so called 'unit-circle'). We take a random point on this circle. We can describe this point uniquely by the angle of the radius through this point and the X-axis, for example 90°, 140°, ...

Mathematically however, radians are used instead of degrees. Without going into much theory, you should just remember that 360° = 2*PI.
So suppose we have a point lying at N radians on our unit circle. Then the X coordinate will be given by cos(N), and the Y coordinate by sin(N). That's the definition of cosine and sine.
So if you want to draw a circle, take every value A from 0 to 2*PI, and plot the points (cos(A), sin(A)). Easy.
The relationship of sine and cosing with right-angled triangles is pretty easy to see. Draw a circle using the origin (0,0) as center. Take a point on this circle, connect the point with the center, project the point on the X axis. Voilà: a right-angled triangle appears :)

Sin and cos have other uses as well. Because they are coordinates of points lying on a circle, they are periodic. A point traveling along a circle will eventually arrive at its starting point. This means that their values are repetive after a while (2*PI to be exact).

So you can use sine and cosine as a source for a pulsing/wavy scope or movement.

The tangent tan is defined as sin divided by cos. It ranges from negative infinity to positive infinity in -PI/2 to PI/2, and repeates itself every PI.

Usually you won't need the actual mathematical uses of these functions, but you'll rather be using their characteristics (e.g. repetiveness).

n_ick2000

10th October 2001 01:57 UTC

Thanks uncloned. That makes more sence to me.

UnConeD

12th October 2001 20:21 UTC

Nick :)
While I'm pretty sure I have not been cloned, I'd appreciate it if you'd stick to my actual nickname :)

n_ick2000

13th October 2001 03:56 UTC

sorry, finger sliped:(

buffer_brazil

28th October 2001 05:34 UTC

I Want to Learn About Sin, Cos
I Want to Make Cool Equations on My AVS Editor but i Don´t Know very few About Sin, Cos, Tan ... Where can I Get Documentation about it??

If You Have Documentation about it, please send me!

Angry Weasel

16th November 2001 22:11 UTC

There's also arcsine(asin), arccosine(acos) and arctangent(atan).

I find that d=atan(d) has a nice effect as demonstrated in Justin's age-old plugin that's no longer available, Gold Shower in Pseudo 3D.

n_ick2000

17th November 2001 02:04 UTC

Justin didn't make it. Lone did. It was in an older version of winamp. Justin removed a blur and added biliner filtering because bilinear filtering wasn't there when lone made it.

Angry Weasel

17th November 2001 14:06 UTC

Sorry...Lone made it but it was sweet.

Kagnar

22nd December 2002 22:56 UTC

This is off the subject, but
I noticed something. If you highlight (click and drag) over a smiley face emoticon, it turns to a sad face! Well, sort of.

UnConeD

23rd December 2002 01:59 UTC

Only in browsers that don't support true alphablending (*cough*IE*cough*)

Kagnar

23rd December 2002 02:52 UTC

What does that mean?

Kagnar

23rd December 2002 02:53 UTC

Oh wait, I got it.

dirkdeftly

23rd December 2002 22:37 UTC

1: Use the edit button
2: Don't revive dead posts for no reason

WHCode RED

24th December 2002 22:09 UTC

ack!
What! This post is a zombie! AAhhhh! (sorry, couldn't help it):p