We worked more examples of using residues to compute real integrals. We stated Jordan's lemma and used it some more examples. The proof of Jordan's lemma will come next week.
We said what we could about essential singularities, including Picard's theorem (Big and Little). We showed that e^{1/z} has an essential singularity at 0 and verified Picard's Big Theorem for it. Next, we started Residue Theory, recalling the residue of a function at a point and the formula for integrating a closed contour in an annulus around that point. We then proved two theorems, the second being Cauchy's Residue Theorem. ;
We started working examples of using the residue theorem to compute integrals. Today, we focused on integrals of type ;
We used residues to compute the Cauchy principal value of improper integrals of rational functions whose denominator has degree two more than the numerator.
We explored isolated singularities that have finite negative parts of their Laurent series, called poles. We defined the order of a pole and a simple pole as a pole of order 1. We proved a lemma saying that a functions norm goes to infinity near a pole, but when multiplied by a certain power of (z - z_0), the pole turns into a removable singularity. We finished by showing that all singularities of rational functions are removable or poles.
We defined power series, radius of convergence, Laurent series and proved various theorem providing the coefficients of such series. We also defined the residue of a function at a point as the -1 coefficient of the Laurent series of the function around the point.
We defined a zero of a function and showed that functions behave predictably near ;zeros. We then defined three kinds of singularities, removable singularities, poles and essential singularities and gave a useful detection result for removable singularities that helps explain the terminology.
We ;defined pointwise and uniform convergence of functions and proved that a sequence of analytic functions converging uniformly on a simply connected domain converges to an analytic function.
We proved Morera's Theorem, gave Cauchy's Derivative Estimate, Liouville's Theorem and the Fundamental Theorem of Algebra.
We derived Cauchy's Integral Formula and used it to compute some integrals. We then started proving some corollaries, including ones that state a analytic is infinitely differentiable and that any function that has an antiderivative is analytic.