Math

• Class Math is in the package java.lang .
• contains math related constants and functions.
• Almost all the members are static.
• Refer to the document for useful methods. Example we have
  • PI, E : pi and e.
  • double cos(double degree), sin, tan... etc : trigonometric functions.
  • max(int,int), max(double, double), min(int, int).. etc.
  • double random() : generate a random number >= 0.0 and < 1.0
  • double pow(double x, double y) return x to the power y

Questions

1. Use one line code to show the result of cos 75 deg
2. Write a method int random(int max) generates a random integer from 1 to max.
3. Write a method double interest(double amount, double interest_rate, int year) returns the interests.

Answer

1. System.out.println(Math.cos(75));

2. int random(int max) {
      return 1 + (int)(max*Math.random()); 
   }
   

3. double interest(double amount, double interest_rate, int year) {
       return amount*Math.pow(1 + interest_rate, year) - amount;
   }