Explain the library java.lang.Math ?
The Java class library is huge. We will not cover it all presently. In fact, the remaining eight classes will focus mostly on the class library. Therefore, I do need to take this opportunity to look briefly at one meaningful class in the library, java.lang.Math. This is a class that contains static methods for performing several standard mathematical operations such as square roots and cosines. You will requires it for several of this weeks exercises.
The Math class contains various dozen static methods. Recall that to use a static techniques from a class, you just prefix its name with the name of the class followed through a period. For instance
double x = Math.sqrt(9.0);
You never required to instantiate the Math class directly. (In fact you can't. The Math() constructor is declared private.)