# Xotor: Algorithms?

No, in High School, I did more chasing girls than studying. I didn't think Trigonometry would ever be useful.

So, the algorithms are as follows?

Ok, radius is the length from the center of

a circle to its edge. I know what degrees and circumference are. What is SIN and COS? Can

it not be explained here? What type of book should I get? Is this beginning trigonometry?

What other math concepts are needed to understand 3D? Most 3D formulas are based on SIN and COS. I know they have to do with circles, right angles and rotation. Help will be appreciated.

• : No, in High School, I did more chasing girls than studying. I didn't think Trigonometry would ever be useful.

:

: So, the algorithms are as follows?

:

: Radius = (3.14 / 180) * Degree; // Degree to radius

: Degree = (180 / 3.14) * Radius; // Radius to degree

:

: Ok, radius is the length from the center of

: a circle to its edge. I know what degrees and circumference are. What is SIN and COS? Can

: it not be explained here? What type of book should I get? Is this beginning trigonometry?

: What other math concepts are needed to understand 3D? Most 3D formulas are based on SIN and COS. I know they have to do with circles, right angles and rotation. Help will be appreciated.

:

You are right, trigonometry is a MUST-KNOW if you want to do 3D programming. Sin, Cosine and Tangant are just the three basic ratios when dealing with triangles, try searching for the topic on the internet, you should be able to find lots of resources.

You got the Radian to Degree alogarthm alright but just one thing, it is RADIAN not Radius. Radian is just another method of measuring angle, 1 radian is equal to the angle of the sector with an arc length equals to the radius. What programming language do you use? But I think many of them use radian when you use their tri functions. So if you try to find the sin of 145 degrees don't go and do sin(145), it will think that you are trying to find the sin of 145 RADIANS!

So, good luck.

anymore questions? [email protected]

• Oh, you are the person who posted a message earlier.. ok then.

• Okay, say you have a right-handed triangle. A right-handed triangle has one angle that is 90 degrees (i.e. perpendicular to the other line) and two other angles.

The long line opposite this 90 degree angle is called the hypotenuse.

The triangle I will refer to now faces the right, in other words there is, what appears to be, an "L" and then a line connecting the top to the right side of the bottom:

|

|_

Using the angle in the bottom right, this is what Sin, Cos, and Tan mean (O = length of side opposite the angle, A = length of side adjacent, [AKA next to], the angle, H = length of hypotenuse):

Sin = O/H

Cos = A/H

Tan = O/A

Some people remember it as SOHCAHTOA like the volcano. Others remember it (myself included) as "Some Old Horse Came A Hoppin' Through Our Alley."

Thus Sin, Cos, and Tan help provide the relation between polar coordinant systems and X/Y ones.

Remember that a circle has 360 degrees and 2pi radians. Zero degrees always starts on the right side and travels counter-clockwise back again. 360 degrees is equivilent to 0 degrees.

-Xotor-

: No, in High School, I did more chasing girls than studying. I didn't think Trigonometry would ever be useful.

:

: So, the algorithms are as follows?

:

: Radius = (3.14 / 180) * Degree; // Degree to radius

: Degree = (180 / 3.14) * Radius; // Radius to degree

:

: Ok, radius is the length from the center of

: a circle to its edge. I know what degrees and circumference are. What is SIN and COS? Can

: it not be explained here? What type of book should I get? Is this beginning trigonometry?

: What other math concepts are needed to understand 3D? Most 3D formulas are based on SIN and COS. I know they have to do with circles, right angles and rotation. Help will be appreciated.

: