Help needed regarding inverse trigonometric functions in PHP (asin, acos etc)

[jawaidpk]

Hi Friends,

 

well I got a problem while using  inverse trigonometric functions like atan, asin etc. in fact the formula which I am using assumed all the calculations would be done in degrees while PHP assumes the input to be provided to the trigonometric functions is Radians. I guess most of you would be thinking about to suggest me to use deg2rad() function, but I think its not the solution.

 

for example

 

in degrees

 

atan(0.4423) = 23.8598

 

but in PHP

 

atan(deg2rad(0.4423)) = 0.0077

 

I need 23.8598 as my answer as I have to use it in the upcoming calculations. if any body can tell me from where I could get those trigonometric functions in PHP which accepts degree as argument rather than radians then it would solve my overall problems. Otherwise it would also be acceptable if anybody can tell me how can I get the same result by using existing atan() and deg2rad or rad2deg functions.

 

 

Thanks in advance

[Zhadus]

You almost have it correct. atan() outputs in radians, you don't put the argument in radians.

e.g.

$arg = 0.4423;
$val = deg2rad(atan($arg));
echo $val; // = 23.8598;

[Barand]

<?php
$arg = 0.4423;                // tangent value
echo rad2deg(atan($arg));     // angle converted to degrees =  23.8598
?>

[Zhadus]

Ack, yeah Barand's is correct. I typoed the rad2deg function.

[jawaidpk]

Hi Zhadus, Barand

 

Thanks buddies, I did'nt read the documentation properly, but your help have resolved my issue.

 

Thanks

Jawed Islam