Just as with mathematical functions, Java methods can be composed. The easiest way to find documentation for Java classes is to do a web search for “Java” and the name of the class. Take a minute to read the documentation for these and other methods in the Math class. The result is 63 (rounded up from 62.8319). More specifically, an int uses 32 bits the largest value it can hold is 2 31−1, which is about 2 billion.Ī long uses 64 bits, so the largest value is 2 63−1, which is about 9 quintillion. double radians = Math.toRadians(180.0) ĭouble degrees = Math.toDegrees(Math.PI) Īnother useful method is round, which rounds a floating-point value to the nearest integer and returns a long. The same is true for the constant Math.E, which approximates Euler’s number.Ĭonverting to and from radians is a common operation, so the Math class provides methods that do it for you. To convert from degrees to radians, you can divide by 180 and multiply by π.Ĭonveniently, the Math class provides a constant double named PI that contains an approximation of π: double degrees = 90 ĭouble angle = degrees / 180.0 * Math.PI Īlso, PI is the name of a variable, not a method, so it doesn’t have parentheses. The third line finds the sine of 1.5 (the value of angle).Īrguments of the trigonometric functions – sin, cos, and tan – should be in radians. The first line sets root to the square root of 17. You can use, or invoke, Math methods like this: double root = Math.sqrt(17.0) ![]() Math is in the java.lang package, so you don’t have to import it. The Java library includes a Math class that provides common mathematical operations. This process can be applied repeatedly to evaluate more complex expressions like log(1/sin(π/2)).įirst we evaluate the argument of the innermost function, then evaluate the function itself, and so on. Then you can evaluate the function itself, maybe by punching it into a calculator. In mathematics, you have probably seen functions like sin and log, and you have learned to evaluate expressions like sin(π/2) and log(1/ x).įirst, you evaluate the expression in parentheses, which is called the argument of the function. ![]() We’ll also present the Math class, which provides methods for common mathematical operations. In this chapter, we’ll show you how to organize longer programs into multiple methods and classes. So far we’ve only written short programs that have a single class and a single method ( main).
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