An erotic actor or erotic actress or a porn star is somebody who appears in pornographic movies. Many actors/actresses may appear nude in films (usually rather briefly) or on stage but even if they depict sexual behavior they are not considered erotic actors. Most erotic actors use stage names.
... term b2 – 4ac is called the discriminant of the quadratic equation, because it discriminates between three qualitatively different cases:
If the ...