Radians: Difference between revisions
>NXTBoy What's the point in presenting the reader with 1° in radians? They don't care! That's just scary numbers! |
>NecroBumpist Provide links to the math lib. Added syntax highlighting. |
||
| (3 intermediate revisions by 2 users not shown) | |||
| Line 18: | Line 18: | ||
In Lua terms, these can be written as: | In Lua terms, these can be written as: | ||
{{lua|= | |||
local radians = degrees * math.pi / 180 | |||
local degrees = radians * 180 / math.pi | |||
}} | |||
However, there is a cleaner way of doing this. Lua provides functions to do these conversions for you in the math library: | However, there is a cleaner way of doing this. Lua provides functions to do these conversions for you in the math library: | ||
| Line 67: | Line 69: | ||
! Angle in degrees !! represents | ! Angle in degrees !! represents | ||
|- | |- | ||
360°|| 2{{pi}} radians | | 360° || 2{{pi}} radians | ||
|- | |- | ||
270°|| 3{{pi}}/2 radians | | 270° || 3{{pi}}/2 radians | ||
|- | |- | ||
180°|| {{pi}} radians | | 180° || {{pi}} radians | ||
|- | |- | ||
90°|| {{pi}}/2 radians | | 90° || {{pi}}/2 radians | ||
|- | |- | ||
60°|| {{pi}}/3 radians | | 60° || {{pi}}/3 radians | ||
|- | |- | ||
45°|| {{pi}}/4 radians | | 45° || {{pi}}/4 radians | ||
|- | |- | ||
30°|| {{pi}}/6 radians | | 30° || {{pi}}/6 radians | ||
|- | |- | ||
0°|| 0 radians | | 0° || 0 radians | ||
|} | |} | ||
== More info== | == More info== | ||
You can convert Degrees to Radians and | You can convert Degrees to Radians and vice versa using [http://www.10ticks.co.uk/radianConverter.aspx online conversion tools], with your calculator, or with the following members of the Lua [[Function_Dump/Mathematical_Functions|math library]]: | ||
=== [[Function_Dump/Mathematical_Functions#math.rad(x)|math.rad(x)]] === | |||
Converts x (in degrees) into Radians. Example: math.rad(90) results in 1.5707963267949. | |||
=== [[Function_Dump/Mathematical_Functions#math.deg(x)|math.deg(x)]] === | |||
math. | Converts x (in Radians) into degrees. Example: math.deg(3.1415926535898) results in 180. | ||
math. | === [[Function_Dump/Mathematical_Functions#math.pi|math.pi]] === | ||
Roblox reads this as Pi, which is 3.1415926535898. | |||
== See Also == | == See Also == | ||
*[[Function_Dump/Mathematical_Functions]] | |||
*[http://en.wikipedia.org/wiki/Radian Radians] | *[http://en.wikipedia.org/wiki/Radian Radians] | ||
*[http://en.wikipedia.org/wiki/Degree_%28angle%29 Degrees] | *[http://en.wikipedia.org/wiki/Degree_%28angle%29 Degrees] | ||
*[http://www.10ticks.co.uk/radianConverter.aspx Radian Degree Converter] | *[http://www.10ticks.co.uk/radianConverter.aspx Radian Degree Converter] | ||
*[http://en.wikipedia.org/wiki/Table_of_polyhedron_dihedral_angles Table of polyhedron dihedral angles] | *[http://en.wikipedia.org/wiki/Table_of_polyhedron_dihedral_angles Table of polyhedron dihedral angles] | ||
Latest revision as of 20:54, 14 April 2012
This is a very basic explanation of Radians, if you have never been taught Radians before.
Radians are another way of describing angles, as opposed to using degrees. Something similar to Radians is used in everyday life, when we use fractions. We say, "I want a third of a piece of cake," not, "I want 120 degrees worth of cake."
In this sense, we are using the concept of "turns". There is one turn in a full circle, so 1 turn is 360°. It follows that 180° is half a turn, 90° is a quarter turn, and so on.
Conversion
One turn is equal to 2π radians. Therefore, 2π radians = 360°. From this, formulae for converting degrees to radians, and vice versa, can be found:
In Lua terms, these can be written as:
local radians = degrees * math.pi / 180
local degrees = radians * 180 / math.pi
However, there is a cleaner way of doing this. Lua provides functions to do these conversions for you in the math library:
local inRadians = math.rad(degrees)
local inDegrees = math.deg(radians)
Radians and Degrees
For a basic idea of Radians to how much "cake" or "circle" you have, divide the radians by "2 pi". To convert how much "cake" or "circle" you have to Radians, multiply the "cake" (or circle) by "2 pi":
| Angle in radians | represents |
|---|---|
| 2π | one whole circle |
| π | one-half circle |
| 2π/3 | one-third circle |
| π/2 | one fourth circle |
| 2π/5 | one-fifth circle |
| π/3 | one-sixth circle |
| 2π/7 | one-seventh circle |
| π/4 | one-eighth circle |
| 2π/9 | one-ninth circle |
| π/5 | one-tenth circle |
| 2π/11 | one-eleventh circle |
| π/6 | one-twelfth circle |
| 0 | No circle |
Degrees slice a circle into 360 parts -- and sometimes degrees need to be converted into Radians. To convert from degrees to radians, divide by (180/pi). To convert from radians to degrees, multiply by (180/π).
For example:
| Angle in degrees | represents |
|---|---|
| 360° | 2π radians |
| 270° | 3π/2 radians |
| 180° | π radians |
| 90° | π/2 radians |
| 60° | π/3 radians |
| 45° | π/4 radians |
| 30° | π/6 radians |
| 0° | 0 radians |
More info
You can convert Degrees to Radians and vice versa using online conversion tools, with your calculator, or with the following members of the Lua math library:
math.rad(x)
Converts x (in degrees) into Radians. Example: math.rad(90) results in 1.5707963267949.
math.deg(x)
Converts x (in Radians) into degrees. Example: math.deg(3.1415926535898) results in 180.
math.pi
Roblox reads this as Pi, which is 3.1415926535898.
