He made large bounds forward in the study of modern analytic geometry and trigonometry where he was the first to consider sin, cos etc. as functions rather than as chords as Ptolemy had done.
Siya na ginawa malaking hangganan forward sa pag-aaral ng mga makabagong analytic geometry at trigonometrya kung saan siya ang unang na isaalang-alang ang kasalanan, atbp cos bilang mga function sa halip na bilang Chords bilang Ptolemy had tapos na.