In 1225 Fibonacci visited the court of the Holy Roman Emperor, Frederick II. Because Frederick was an important patron of learning, this visit was important to Fibonacci. During the audience, Frederick's court mathematician posed three problems to test Fibonacci. The third was to find the real solution to x3 + 2x2 + 10x = 20. In an earlier CMJ article, Brown and Brunson discussed several methods that Fibonacci might have used to find his estimate for the solution to this problem and conjectured that the method of Elchataym was the one that Fibonacci actually used. This article continues this discussion and proposes another method, not mentioned by Brown and Brunson, but likely known to Fibonacci and more likely to be the one that he actually used.
The College Mathematics Journal is designed to enhance classroom learning and stimulate thinking regarding undergraduate mathematics. CMJ publishes articles, short Classroom Capsules, problems, solutions, media reviews and other pieces. All are aimed at the college mathematics curriculum with emphasis on topics taught in the first two years.