Touring Language APIs - Beginning Java 7 - page 308

Table4-1 revealsawidevarietyofusefulmath-orientedmethods.Forexample,each
abs() method returns its argument's absolute value (number without regard for sign).
abs(double) and abs(float) are useful for comparing double precision
floating-pointandfloating-pointvaluessafely.Forexample, 0.3 == 0.1+0.1+0.1
evaluates to false because 0.1 has no exact representation. However, you can compare
these expressions with abs() and a tolerance value, which indicates an acceptable
range of error. For example, Math.abs(0.3-(0.1+0.1+0.1)) < 0.1 returns
truebecausetheabsolutedifferencebetween 0.3 and 0.1+0.1+0.1 islessthana0.1
tolerance value.
Previous chapters demonstrated other Math methods. For example, Chapter 2
demonstrated Math 's random() , sin() , cos() , and toRadians() methods.