The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
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The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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c. 1260-c. 1320
Islamic mathematician and optical thinker who made important contributions to number theory and the optics of the rainbow. A pupil of the astronomer and mathematician Qutb al-Din al-Shirazi (1236-1311), he is best known for his nearly correct explanation of the optical mechanism of the rainbow, which followed from his exhaustive critical study of ibn al-Haytham's (965-1039) great Optics and writing his own Revision of Optics. He correctly noted the fundamental idea that the appearance of a rainbow was due to two refractions of light on a cloud droplet but he was not sure of the number of reflections and was incorrect in his explanation for the colors of the rainbow. Al-Farisi also made important contributions to number theory, introducing ideas concerning factorization and combinatorial methods.