Person: De Ortega, Juan
Juan de Ortega was a Spanish mathematician who devised an original method of extracting square roots.
Mathematical Profile (Excerpt):
 It was one of the major Orders within the Roman Catholic Church, and it was very active in the universities where its members were soon concentrated.
 The Dominican order was a collection of priests, organized in provinces under a master general.
 Members of the Order were sent wherever they were needed.
 Often those who wished to teach in universities in the fifteenth century would join the Dominican Order, for those in the Order taught not only theology but also philosophy and the other ancient branches of learning.
 Juan de Ortega had no university education and, as a Dominican with a vow of poverty, needed little in the way of an income as a Friar.
 Although we do not have details of his travels we do know that he was abroad at various times teaching both in Spain and Italy.
 Almost certainly had a teaching post within the Dominican Order but he tutored privately as well.
 Ortega's book A Tractado subtilisimo d'arithmetica y de geometria published in Barcelona in 1512 covered commercial arithmetic and the rules of geometry.
 The first part of the book contains practical rules for calculations necessary for trade and includes conversion tables between the different Spanish currencies.
 In the second part of the book, devoted mostly to geometry, Ortega gives a method of extracting square roots very accurately using Pell's equation, which is surprising since a general solution to Pell's equation does not appear to have been found before Fermat over 100 years later.
 Very little is known about Ortega and it appears that his importance rests entirely on the interesting method for taking square roots.
 Chuquet also devised a similar algorithm which appears in Triparty which was probably written no later than May 1484.
 Ortega also published Cursus quattuor mathematicarum artium liberalium published in Paris in 1516.
Born 1480, Palencia (now Spain). Died 1568.
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Origin Spain
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References
Adapted from other CC BYSA 4.0 Sources:
 Oâ€™Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive