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Thread: calculate sin(x)

  1. #1
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    Question calculate sin(x)

    How can I transform this code to calculate the sin(x) in the method?

    public static double getCos(double degrees, int n) {
    double cos = 0;
    double numerator = 0;
    int denominator = 0;
    for (int i = 0; i <= n; i++, i++) {
    numerator = getNumerator(degrees, i);
    denominator = getFactorial(2 * i + 1);
    cos += numerator / denominator;


  2. #2
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    Default Re: calculate sin(x)

    Can you use the Math class's method?

    Otherwise what is the algorithm for the computation? Where are you having problems coding it?


    Please edit your post and wrap your code with code tags:
    [code=java]
    YOUR CODE HERE
    [/code]
    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: calculate sin(x)

    package cosx;
     
    import java.util.Scanner;
     
    public class cosx2 {
     
    	public static void main(String[] args) {
    		Scanner input = new Scanner(System.in);
     
    		System.out.print("Enter the degree: ");
    		double degree = input.nextDouble(); 
     
    		double radian = getRadian(degree);
     
    		calculateCos(input, radian,degree);
     
    	}
     
     
    	public static double getRadian(double x) {		
    		return x = (Math.PI/180)*x;		
    	}
     
    	private static void calculateCos(Scanner std, double rad, double deg) {
    		System.out.print("How many terms do you want to calculate the cos: ");
    		int terms = std.nextInt();
    		double top;
    		double bottom;
    		double sum=0;
     
    		for(int i = 0; i<= terms; ++i){
    			top = Math.pow(-1, i);			
    			bottom =1;
    			int repeat = 2*i+1;
    			for(int j = 1; j <= repeat; ++j){				
    				bottom *= j; 
    			}
    			if(i%2 == 0)
    				sum += (top/bottom);
    			else
    				sum -= (top/bottom);
    		}
    		System.out.printf("The sin (%.1f", deg);
    		System.out.printf(") is %.6f", sum);		
    	}
    }

    I cannot figure out how to input the function to calculate the cosine?

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    Default Re: calculate sin(x)

    how to input the function to calculate the cosine?
    What do you mean by "input the function"?
    Are you trying to type code for a method into an editor?
    Are you trying to pass data as input to a method?
    Please explain.

    The attachment is useless. Too small.
    If you don't understand my answer, don't ignore it, ask a question.

  6. #6
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    Default Re: calculate sin(x)

    If you click the image it will expand....
    import java.util.Scanner;
     
    public class cosx2 {
     
    	public static void main(String[] args) {
    		Scanner input = new Scanner(System.in);
     
    		System.out.print("Enter the degree please: ");
    		double degree = input.nextDouble(); 
     
    		double radian = getRadian(degree);
     
    		calculateCos(input, radian,degree);
     
    	}
     
     
    	public static double getRadian(double x) {		
    		return x = (Math.PI/180)*x;		
    	}
     
    	private static void calculateCos(Scanner std, double rad, double deg) {
    		System.out.print("How many terms do you want to calculate the cos: ");
    		int terms = std.nextInt();
    		double num;
    		double den;
    		double sum=0;
     
    		for(int i = 0; i<= terms; ++i){
    			num = Math.pow(-1, i);			
    			den = factorial(2*i);
    			int repeat = 2*i+1;
    			for(int j = 1; j <= repeat; ++j){				
    				den *= j; 
    			}
    			if(i%2 == 0)
    				sum += (num/den);
    			else
    				sum -= (num/den);
    		}
    		System.out.printf("The cos (%.1f", deg);
    		System.out.printf(") is %.6f", sum);
    		System.out.println("The calcuated value of cos was " +sum+ 
    				" Howver the real value of cose was " + Math.cos(deg));
     
    	}
    }
    Screen Shot 2013-11-06 at 11.11.44 AM.jpg
    Attached Images Attached Images

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    Default Re: calculate sin(x)

    How are you debugging the code? I use println() statements to print out intermediate results to validate the code. Does the code compute each term in the series correctly? Print out the first few and manually verify that they are correct.

    The code should include comments showing the series that is being computed.

    It is impossible to copy the series shown in an image to be able to add it as comments to the code.
    If you don't understand my answer, don't ignore it, ask a question.

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