public class MyMathTest{
   public static void main (String args [])
    {
               
        System.out.println("El sumatorio de 5 es " + MyMath.sum(5));
        System.out.println("El factorial de 5 es " + MyMath.factorial(5));
        System.out.println("La potencia de 4 elevado a 5 es " + MyMath.power(4, 5));
        System.out.println("El sen (5, 6) es " + MyMath.sin(5, 6));
        System.out.println("El cos (5, 6) es " + MyMath.cos(5,6));
     }

}

class MyMath {

    /** Crear un nuevo MyMath */
    public MyMath() {
    }
    
    public static int sum(int n)
    {
        if (n==1)
            return 1;
        return (n+sum(n-1));
       
    }
    
    public static int factorial(int n) 
         { 
           // calcula el factorial de n 
           if(n==0) 
               return 1; 
            return ( n * factorial(n-1)); 
         } 

    public static int power(int a, int b)
    {
        if (b==0)
            return 1;
        return (a*power(a, b-1));
    }
     
    public static double sin (double angle, int i) 
          { 
             // Función recursiva para calcular el seno
           if(i==1) 
              return angle; 
           else 
              return(Math.pow(-1,i+1)*Math.pow(angle,2.0*i-1.0)/ 
                factorial(2*i-1)+sin(angle,i-1)); 
          } 
          
     public static double cos (double angle, int i)
     
        { 
           // Función recursiva para calcular el coseno
           if (i==1)
               return 1;
           else
               return (Math.pow(-1,i+1)*Math.pow(angle,(2.0*i-2.0)) /
               factorial(2*i-2)+cos(angle, i-1));
            
         } 
}