The correct question is, Why (or when) is it useful to view [math]\cos^2(x)[/math] as a composite function? In calculus, it is useful when taking the derivative of [math]f(x) = \cos^2 x[/math] to recognize that [math]f(x)[/math] is a composition of two functions whose derivatives we (presumably) already know.
In law, fraud is deliberate deception to secure unfair or unlawful gain. Fraud is both a civil wrong (i.e., a fraud victim may sue the fraud perpetrator to avoid the fraud and/or recover monetary compensation) and a criminal wrong (i.e., a fraud perpetrator may be prosecuted and imprisoned by governmental authorities).n common law jurisdictions, as a criminal offence, fraud takes many different forms, some general (e.g., theft by false pretense) and some specific to particular categories of victims or misconduct (e.g., bank fraud, insurance fraud, forgery).
The purpose of fraud may be monetary gain or other benefits, such as obtaining a passport or travel document, driver's license or qualifying for a mortgage by way of false statements. A hoax is a distinct concept that involves deliberate deception without the intention of gain or of materially damaging or depriving a victim.