/**

* Write a method to compute the sum of the series in a class called SpecialSeries.

*

* sum = x + [1/2] * (x<3>/3) + [(1*3)/(2*4)] * (x<5>/5) + [(1*3*5)/(2*4*6)] * (x<7>/7) + ...

*

* The signature of the method is:

* public static double sumOfSeries(double x, int numTerms)

*/

package javaexercises.difficult;

/**

*

* @author User

*/

public class SpecialSeries {

public static void main(String[] args)

{

SpecialSeries aSpecialSeries = new SpecialSeries();

double x = 0.1D;

System.out.printf("Sum of the series: %.9f \n"

, aSpecialSeries.sumOfSeries(x, 5));

}

private double calculateTerm(double x, int numTerms)

{

double term = 1D;

for (int i = (2*numTerms+1); i > 0; i--) {

term *= x*(i%2 == 0 ? 1 : i)/(i%2 == 0 ? i : 1);

}

term /= 2*(2*numTerms+1);

return term;

}

private double sumOfSeries(double x, int numTerms)

{

if (x < -1D || x > 1D) {

System.out.println("Please ensure what x value in range [-1; 1] and try again.");

return 0D;

}

double result = 0D;

for (int i = 0; i < numTerms; i++) {

result += calculateTerm(x, i);

}

return result;

}

}