Most real problems do not have a neat formula as their answer, so we approximate. Numerical methods turn calculus into step by step procedures a computer can carry out, together with a way to judge how large the error is.
This unit covers reliable use of software, root finding with bisection and Newton's method, approximate derivatives and integrals, Taylor approximation, and Euler and Runge-Kutta methods for differential equations.
Every lesson will be a pair of videos, a theory part that explains the idea and a practice part that works through problems. The videos are coming soon, and each lesson page already has the definitions and an example for every key term.
Reliable Computation
Graphing Software and Numerical Reliability
How a computer graph is made from finitely many rounded samples, how it can hide or invent features, and how the derivative theorems turn what a graph suggests into a proof.
Theory part 243Practice part 244
Root Finding
Bisection and Newton’s Method
How to solve f(x) = 0 when no formula gives the root, with bisection as the slow method that cannot fail and Newton's method as the fast one that needs a good start.
Theory part 245Practice part 246
Numerical Differentiation
Finite Differences and Derivative Approximation
How to estimate a derivative from function values or measured data with forward, backward and central differences, and why making the step size smaller helps only up to a point.
Theory part 247Practice part 248
Numerical Integration
Integral Approximation Rules
How the midpoint, trapezoidal and Simpson's rules approximate a definite integral, how derivative bounds tell you how many subintervals are enough, and how adaptive methods put the work where it is needed.
Theory part 249Practice part 250
Approximating Improper Integrals
How to approximate an integral over an infinite interval or with an unbounded integrand by cutting off a tail you can bound, removing singularities, and keeping track of each source of error.
Theory part 251Practice part 252
Approximation with Series
Approximating Using Taylor’s Formula
How Taylor polynomials with a remainder bound give function values and integrals to a guaranteed accuracy, and how to pick the center and the degree to meet a given tolerance.
Theory part 253Practice part 254
Numerical Differential Equations
Euler and Runge-Kutta Methods
How Euler's method and its improved and Runge-Kutta versions step along a solution of y' = f(x, y), how their errors shrink as the step gets smaller, and when a step is too large to be stable.
Theory part 255Practice part 256