Hello all you Java programmers out there. I have a tiny problem. The code is not allowing me to use the cos(double x) and acos(double x) methods even though I imported the math class. So....Whats wrong with my code???

/*

* Andre Taylor

* 10/26/2010

* This program is a prototype that is designed to use the law of cosines to solve oblique triangles

* The user inputs the given values and the program computes and displays

* solved triangle

*/

package obliquetrianglescosine;

import java.lang.Math; //*Imported to use cosine and arccosin methods

//Its not working for some reason. it Says unused port even though I

//call for the cos and arccos method

import java.util.Scanner;

/**

*

* @author owner

*/

public class cosineLaw {

/**

* @param args the command line arguments

*/

public static void main(String[] args) {

double a; //Declare variables for values given

double b;

double c;

double A;

double B;

double C;

System.out.println("So what info was given to you? If nothing is input put 0 where value is."); //User inputs info given if nothing given user inputs 0

System.out.print("a:");

Scanner input = new Scanner (System.in);

a= input.nextDouble();

System.out.print("b:");

b= input.nextDouble();

System.out.print("c:");

c= input.nextDouble();

System.out.print("A:");

A= input.nextDouble();

System.out.print("B:");

B= input.nextDouble();

System.out.print("C:");

C= input.nextDouble();

computeLastSide( a, b, C, c);

computeSecondAngle( a, b, c,A);

computeLastAngle( A, B, C);

System.out.println("Side c= "+c);

System.out.println("Angle A= "+A);

System.out.println("Angle B= "+B);

}

public static double computeLastSide(double a,double b,double C, double c) //computes the last side of triangle

{

c =(a*a+b*b)-2*a*b*cos(C);

return c;

}

public static double computeSecondAngle(double a, double b, double c, double A) //computes second angle

{

A = acos(((b*b+c*c)-a*a)/2*b*c);

return A;

}

public static double computeLastAngle(double A, double B, double C) //computes last angle

{

B= 180-A-C;

return B;

}

}