CS 100: Lecture L7

February 16

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// Lecture 7

import java.io.*;

public class L7
{
	public static void main(String args[])
	{
	   TokenReader in = new TokenReader(System.in);
	   
	   double g = 30.1;
	   MyTrig.displayDeg(g);
	   MyTrig.displayDeg(2*g+10);
		
		
	   double theta = 60;
	   double c = MyTrig.cosD(theta);
	   System.out.println("cos(60) = " + c);
	   c = MyTrig.cosD(2*theta-30);
	   System.out.println("cos(2*60-30) = " + c);
	   double rads = MyTrig.DEG2RAD*90;
	   System.out.println("90 degrees = " + rads + " radians");
	   
	   
	   double a = Math.PI/6;
	   int b = MyTrig.nearest(a);
	   System.out.println("Nearest degree to pi/6 = " + b);
	   
	   
	   double latitude = MyTrig.convert(42,12,39);
	   double dist = 3950*latitude*MyTrig.DEG2RAD;
	   System.out.println("Our distance to equator = " + dist + " miles");
	   	
	   double dist2Axis = 3950*MyTrig.cosDMS(42,12,39);
	   System.out.println("Distance to axis = " + dist2Axis + " miles");
	   
	   in.waitUntilEnter();
	}

}

/*
The angle is 30.1 degrees
The angle is 70.2 degrees
cos(60) = 0.5000000000000001
cos(2*60-30) = 6.123031769111886E-17
90 degrees = 1.5707963267948966 radians
Nearest degree to pi/6 = 30
Our distance to equator = 2910.036185625097 miles
Distance to axis = 2925.676424829559 miles
*/

public class MyTrig
{
   // Constants for converting degrees to radians and vice versa.
   public static final double DEG2RAD = Math.PI/180;  
   public static final double RAD2DEG = 180/Math.PI;

   // Displays the value of x, assumed to be in degrees
   public static void displayDeg(double x)
   {
      System.out.println("The angle is " + x + " degrees");
   }
   
   // Yields the cosine of x assuming x given in degrees.
   public static double cosD(double x)
   {
      double y;
      y = Math.cos(DEG2RAD*x);
      return y;
   }
   
   // Yields the value of x (radians) to the nearest degree.
   public static int nearest(double x)
   {
      int a;
      a = (int) Math.round(RAD2DEG*x);
      return a;
   }
   
   // Yields the degree equivalent of d degrees + m minutes + s seconds.
   public static double convert(int d, int m, int s)
   {
      double z;
      z = d + (double)m/60 + (double)s/3600;
      return z;
   }
   
   // Yields the cosine of d degrees + m minutes + s seconds.
   public static double cosDMS(int d, int m, int s)
   {
      double t;
      t = cosD(convert(d,m,s));
      return t;
   }
   
}