Modern classical music is music written in the 20th century and beyond. Although much of it draws heavily on earlier forms, modern composers also experimented with rejection of long-held ideas; notably, Arnold Schoenberg questioned the traditional notions of harmony with his twelve-tone system[?], and John Cage questioned the very definition of music with his use of chance and found sounds.
... {b^2-4ac}}{2a}
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The term b2 – 4ac is called the discriminant of the quadratic equation, because it discriminates between three qualitatively ...