Help in Math Function

I got a function from internet that I need to embed in my app code, but the function is not clear.

RA = arctan2(cos(e) sin(L), cos(L))/ 15*

What is the purpose of , between Sin and Cos of L?

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Show the source (link) for the equation, and its intended application.

Check the math drawer, you will find the atan2 block, you will know why.

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Here is the link of the page:
Prayer Time Calculation Page

You may search for the text
RA = arctan2(cos(e) sin(L), cos(L))/ 15*
on the web page.

Intended Purpose:
It is a variable used in calculation of Equation of Time

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The comma ( , ) is used to separate two parameters in this case.

For a method, m(var a, var b)
Comma is a punctuator that separates two parameters (input variables).

Thanks for the quick answer, Now which one will be input Y and which one will be X? Does order maters or not?

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Read what is written in the image below.

Ref :

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It is x, and

is y.


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In function order maters.

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It would be cos(e) * sin(L) by the way...

I doubt it, should it not be reversed?

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I think you can veryfy using the sample data provided in


d = jd - 2451545.0; // jd is the given Julian date

g = 357.529 + 0.98560028* d;
q = 280.459 + 0.98564736* d;
L = q + 1.915* sin(g) + 0.020* sin(2*g);

R = 1.00014 - 0.01671* cos(g) - 0.00014* cos(2g);
e = 23.439 - 0.00000036
RA = arctan2(cos(e)* sin(L), cos(L))/ 15;

D = arcsin(sin(e)* sin(L)); // declination of the Sun
EqT = q/15 - RA; // equation of time

you are to provide data according to AI2 function


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