Using Sin() with degrees

[monoceres]

I'm currently writing a simple triangle solver app, but I'm having troubles when using the law of sines ( a/Sin(A) = b/Sin( ).

Here's my problem:

#include <math.au3>
; When testing this on my calculator I get around 19 which is correct but this doesn't (-4.03)
MsgBox(0,"",(10/_Degree(Sin(10)))*_Degree(Sin(160)))
; Oh and neither does this:
MsgBox(0,"",(10/Sin(10))*Sin(160))
; This works however:
MsgBox(0,"",(10/_Degree(Sin(10)))*_Degree(Sin(10)))

I know it's the stupid radians fault but how do I fix it?

Edited April 28, 2008 by monoceres

[evilertoaster]

When you use the Sin() function, you must always give it a paramater in radians, and it will always return a number in radians. I see at some points you are using 160 which is most likely degrees. Make sure you pay close attention to which numbers you use as paramaters.

[monoceres]

When you use the Sin() function, you must always give it a paramater in radians, and it will always return a number in radians. I see at some points you are using 160 which is most likely degrees. Make sure you pay close attention to which numbers you use as paramaters.

Of course how foolish of me.

Thanks for looking into it

[weaponx]

Take a look at this:

#463161

[The Kandie Man]

When you use the Sin() function, you must always give it a paramater in radians, and it will always return a number in radians. I see at some points you are using 160 which is most likely degrees. Make sure you pay close attention to which numbers you use as paramaters.

@Everyone, especially monoceres

This is not so. Sin(x) does not return a number in any particular unit. It merely returns the value of the ratio of the length of the opposite side to the length of the hypotenuse of one of the non right angles in a right triangle whose angle measure is x. The angle measure is traditionally given in radians for Sine, Cosine, and Tangent functions because radians are the natural units of a circle. The only reason we use degrees is because the greeks had some fascination with using degrees instead of the more natural radians.

In the world of the unit circle, Sin() is the value of the y coordinate on the unit circle while Cos() is the value of the x coordinate on the unit circle. Tan() is equal to the slope of the angle on the unit circle.

I know you are frustrated about using radians instead of degrees, but please use the radians. They really are much more natural and much better than degrees.

Anyway, to help you, i have made this:

ConsoleWrite(Round(Cos(_DegreesToRadians(90)),2)&@LF)

ConsoleWrite(_RadiansToDegrees(2*3.14159265358979)&@LF)

Func _DegreesToRadians($nDegrees)
    Local $pi = 3.14159265358979
    Return $nDegrees * $pi / 180 ; pi is equal to 180 degrees.  So remove the 180 and multiply the remaining value by pi(I did this backwards, but it doesn't matter).
EndFunc

Func _RadiansToDegrees($nRadians)
    Local $pi = 3.14159265358979
    Return $nRadians * 180 / $pi ; pi is equal to 180 degrees.  So remove the pi and multiply the remaining value by 180(I did this backwards, but it doesn't matter).
EndFuncoÝ÷ Ù¦zfÞ­× ­ç¬jwkiØÆ«z)éºÛ(~Ø^~éܶ*'J)Þ
"æ§u6§éíhºÚn¶Äáz­¦ëlj·­®((¶¸­«b¢Çè­ªâm®&§W¨­Ê(­Ø§j׬¢»%¢¬¢v®+·%{br¯z¼(®Wr¢æ«{
+)àqÞ­è¬Ê«{¦¦WèqêÞ±«­¢+Ù5Í    ½à À°ÅÕ½ÐìÅÕ½Ðì° ÄÀ½M¥¸¡}ÉÍQ½I¥¹Ì ÄÀ¤¤¤©M¥¸¡}ÉÍQ½I¥¹Ì ÄØÀ¤¤¤()Õ¹}ÉÍQ½I¥¹Ì ÀÌØí¹É̤(%1½°ÀÌØíÁ¤ô̸ÄÐÄÔäÈØÔÌÔàäÜä(%IÑÕɸÀÌØí¹Ę́ÀÌØíÁ¤¼ÄàÀ)¹Õ¹

It does give the answer as something around 19. I hope this answered your question.

- The Kandie Man ;-)

[monoceres]

@Everyone, especially monoceres

This is not so. Sin(x) does not return a number in any particular unit. It merely returns the value of the ratio of the length of the opposite side to the length of the hypotenuse of one of the non right angles in a right triangle whose angle measure is x. The angle measure is traditionally given in radians for Sine, Cosine, and Tangent functions because radians are the natural units of a circle. The only reason we use degrees is because the greeks had some fascination with using degrees instead of the more natural radians.

In the world of the unit circle, Sin() is the value of the y coordinate on the unit circle while Cos() is the value of the x coordinate on the unit circle. Tan() is equal to the slope of the angle on the unit circle.

I know you are frustrated about using radians instead of degrees, but please use the radians. They really are much more natural and much better than degrees.

Anyway, to help you, i have made this:

ConsoleWrite(Round(Cos(_DegreesToRadians(90)),2)&@LF)

ConsoleWrite(_RadiansToDegrees(2*3.14159265358979)&@LF)

Func _DegreesToRadians($nDegrees)
    Local $pi = 3.14159265358979
    Return $nDegrees * $pi / 180 ; pi is equal to 180 degrees.  So remove the 180 and multiply the remaining value by pi(I did this backwards, but it doesn't matter).
EndFunc

Func _RadiansToDegrees($nRadians)
    Local $pi = 3.14159265358979
    Return $nRadians * 180 / $pi ; pi is equal to 180 degrees.  So remove the pi and multiply the remaining value by 180(I did this backwards, but it doesn't matter).
EndFuncoÝ÷ Ù¦zfÞ­× ­ç¬jwkiØÆ«z)éºÛ(~Ø^~éܶ*'J)Þ
"æ§u6§éíhºÚn¶Äáz­¦ëlj·­®((¶¸­«b¢Çè­ªâm®&§W¨­Ê(­Ø§j׬¢»%¢¬¢v®+·%{br¯z¼(®Wr¢æ«{
+)àqÞ­è¬Ê«{¦¦WèqêÞ±«­¢+Ù5Í    ½à À°ÅÕ½ÐìÅÕ½Ðì° ÄÀ½M¥¸¡}ÉÍQ½I¥¹Ì ÄÀ¤¤¤©M¥¸¡}ÉÍQ½I¥¹Ì ÄØÀ¤¤¤()Õ¹}ÉÍQ½I¥¹Ì ÀÌØí¹É̤(1½°ÀÌØíÁ¤ô̸ÄÐÄÔäÈØÔÌÔàäÜä(IÑÕɸÀÌØí¹Ę́ÀÌØíÁ¤¼ÄàÀ)¹Õ¹

It does give the answer as something around 19. I hope this answered your question.

- The Kandie Man ;-)

Thanks for the answer. I already solved it using the function _radian() which I guess does exactly like the same as your function.

Anyways, I'm almost done with my Triangle Solver, posting it later

[monoceres]

Thanks for the help

I've just posted my Triangle Solver