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Mathematische Funktionen




(PHP 4, PHP 5)



float atan ( float $arg )

Berechnet den Arkustangens von arg. atan() ist die Komplementärfunktion zu tan(), d.h. für alle Werte im Wertebereich von atan() gilt a==tan(atan(a)).



Der zu verarbeitende Wert


Der Arkustangens von arg in Bogenmaß.

Siehe auch

3 BenutzerBeiträge:
- Beiträge aktualisieren...
joelperr at kiwi-interactif dot com
12.01.2006 2:12
to obtain the direction of the line, you are better to use the <? atan2((y2-y1)/(x2-x1)) ?> function, since the regular atan function will only return arguments in the half-plane, ie. if y2-y1 and x2-x1 are negative, atan will give you an angle measurement less than 90 degrees, while it really should be  between 180 and 270
darren_wheatley at hotmail dot com
28.11.2003 3:24
Arc Tan curve manipulation.

I used this formula to help with increasing and then diminishing return for y given an increasing x for a game.

Ie: Food production (output) is y. Food research is x.

The more research you put into x the more you produce, however after a certain point you get less reward.

 y = atan(x - pi()) + pi()/2;

The + pi()/2 moves it up the y axis so you'd add more if you want it to start higher.

The x - pi() moves it to the right so you'd minus more to move it more.

If you want stretched along the y axis change it to 2 * atan( ...... )

Dunno how useful it is... but it's there.

jmartin at columbiaservices dot net
21.11.2003 9:10
I looked for hours trying to come up with a formula to solve the direction that a line was heading (in degrees) when x1,y1 were the starting points, and x2,y2 are the ending points. Here is the equasion I was given, I hope this helps anyone in need of the same one.

$angle = rad2deg(atan2(($y2 - $y1), ($x2 - x1)));

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