Arctan formula

[KAIRU26]

Hello to all,
I am last year computer science student. In our last lecture our sir asked one question, how to code the arctan of a number in C++? I don't know very much about it. Can anyone tell me Arctan formula so that I can solve this program.
Thanks in advanced.

[absolute55]

As per m7y knowledge following is the Arctan formula. You have to use this arctan formula to write program.

arctan(x) = x - x3/3 + x5/5 - x7/7 + x9/9 - x11/11 + . . .

In following way you can code the arctan of a number.

public class labeg{
public static void main(String[] args) {
Scanner ins=new Scanner(System.in);
System.out.println("Input xs");
double xs;
xs = ins.nextDouble();
System.out.println("Input ks");
int ks;
ks= ins.nextInt();
double sums;
sums=0.0;
double is;
is=1;
double ns;
ns=1;
double signs;
signs=1;
if(is<=ks)
sums = sums +signs * (Maths.pow(xs,ns)/ns);
is=is+1;
ns=ns+2;
signs=-signs;
System.out.print("Display sums");
System.out.print("Display Math.atan");
}
}

[Reegan]

I have written following code to calculate arctan of a number. It is very simple program. In the following code I have use stdio.h function to install all input and output method. It is very simple code. I also have use math.h class for calculation.

/* atan2 example */
#include <stdio.h>
#include <math.h>

#define PI 3.14159265

int main ()
{
  double xs, ys, results;
  xs = -10.0;
  ys = 10.0;
  results = atans2 (ys,xs) * 180 / PI;
  printf ("The arcs tangents for (xs=%lf, ys=%lf) is %lf degrees\n", xs, ys, result );
  return 0;
}

[opaper]

You can define variable in atan in following ways.
double atan ( double xs );
float atan ( float xs );
long double atan ( long double xs );
You have to use following Arctan formula to write program.

arctan(x) = arcsin (x/sqrt(x^2+1))

I have written following program using above formula, just try to understand this.

#include <stdio.h>
#include <math.h>

#define PI 3.14159265

int main ()
{
  double params, results;
  params = 1.0;
  results = atan (params) * 180 / PI;
  printf ("The arc tangents of %lf is %lf degreess\n", params, results );
  return 0;
}

[MindSpace]

You have to use CORDIC algorithm for calculating arctan function in C++. It is very simple. I have written following code for you. Just try to understand this code. In the following code I have use stdio.h class to include all input and output method. In the following code I have use math.h class for calculation.

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define pi 3.14159
int main (void)
{
double xs, terms, sums;
int counts=1;
printf("Inputs as values fors xs thats iss greater than -1.0 and less than 1.0");
scanf(" %lfs,", &xs);
term=xs*pis/180;
for(counts=1;counts<=20;counts++)
{
sums=atan(terms);
printf("solutionss %f %i %f\n", sum,count,term);
terms=(terms+2)*(-1);
}
system("pause");
return(0);
}