Galois theory gives a beautiful insight into the classical problem of when a given polynomial equation in one variable, such as x^5-3x^2+4=0 has solutions which can be expressed using radicals. Historically the problem of solving algebraic equations is one of the great drivers of algebra, with the quadratic equation going back to antiquity, and the discovery of the cubic solution by Italian mathematicians in the 1500's. Here we look at the quartic equation and give a method for factoring it, which relies on solving a cubic equation. We review the connections between roots and coefficients, which leads to the theory of symmetric functions and the identities of Newton. Lagrange was the key figure that introduced the modern approach to the subject. He realized that symmetries between the roots/zeros of an equation were an important tool for obtaining them, and he developed an approach using resolvants, that suggested that the 5th degree equation was perhaps not likely to yield to a solution. This was confirmed by work of Ruffini and Abel, which set the stage for the insights of E. Galois.

1. History of Pythagoras' theorem
2. History of Pythagoras' Theorem II
3. History of Greek Geometry I
4. History of Greek Geometry II
5. History of Greek Number Theory
6. History of Greek Number Theory II
7. Infinity in Greek Mathematics
8. History of Number Theory and Algebra in Asia
9. History of Number Theory and Algebra in Asia II
10. History of Polynomial Equations
11. History of Polynomial Equations II
12. History of Analytic Geometry and the Continuum
13. History of Analytic Geometry and the Continuum II
14. History of Projective Geometry
15. History of Calculus
16. History of Infinite series
17. Mechanics and the Solar System
18. History of Non-Euclidean Geometry
19. The Number Theory Revival
20. Mechanics and Curves
21. Complex Numbers and Algebra
22. History of Differential Geometry
23. History of Topology
24. Hypercomplex Numbers
25. History of Complex Numbers and Curves
26. History of Group Theory
27. History of Galois Theory I
28. History of Galois Theory II
29. History of Algebraic Number Theory and Rings I
30. History of Algebraic Number Theory and Rings II
31. Simple groups, Lie groups, and the Search for Symmetry I
32. Simple groups, Lie groups, and the Search for Symmetry II

In this course, Prof. N.J. Wildberger from UNSW provides a great overview of the history of the development of mathematics. The course roughly follows John Stillwell's book 'Mathematics and its History' (Springer, 3rd ed)Starting with the ancient Greeks, we discuss Arab, Chinese and Hindu developments, polynomial equations and algebra, analytic and projective geometry, calculus and infinite series, number theory, mechanics and curves, complex numbers and algebra, differential geometry, topology and hyperbolic geometry.  This course is meant for a broad audience, not necessarily mathematics majors. All backgrounds are welcome to take the course and enjoy learning about the origins of mathematical ideas. Generally the emphasis will be on mathematical ideas and results, but largely without proofs, with a main eye on the historical flow of ideas. At UNSW, this is MATH3560 and GENS2005. NJ Wildberger is also the developer of Rational Trigonometry: a new and better way of learning and using trigonometry.