Linear transformations in two dimensions are defined by transforming lines into lines. If we look at things more in a polar-coordinates, complex-numbers way, we find another set of transformations which transform shapes of a particular simple sort into shapes of the same sort. Continue reading

# Monthly Archives: August 2015

# Three other (more traditional) proofs of circle of Apollonius

We prove that if the locus of z is a circle, then the locus of w=(az+b)/(cz+d) is a circle (or line). Continue reading