proof Archives - Infinity is Really Big

June 20, 2019September 12, 2019

Matrices and Linear Transformations in Low Dimensions

Visual Linear Algebra Online, Section 1.5

The null space (kernel) of the linear transformation defined by $T\left(\begin{array}{c} x \\ y \end{array}\right)=2x+y$ is a straight line through the origin in the plane ${\Bbb R}^{2}$ .

T\left(\begin{array}{c} x \\ y \end{array}\right)=2x+y — The null space (kernel) of the linear transformation defined by $T\left(\begin{array}{c} x \\ y \end{array}\right)=2x+y$ is a straight line through the origin in the plane ${\Bbb R}^{2}$ .

In mathematics, a matrix is not a simulated reality, but instead just a plain-old rectangular array of numbers. This does not mean, however, that mathematical matrices are uninteresting.

In fact, we … Read the rest

March 22, 2019March 25, 2019

De Morgan’s Laws and Commutative Diagrams

New Videos: Videos #3 and #4 on Probability for Actuarial Exam 1/P

As I emphasized in my most recent post “Venn Diagrams and Probability Notation“, simple probability problems are often best solved with pictures and basic logic, but more complicated problems may require formulas.

We are definitely not at the point in my video series where more complicated … Read the rest

January 15, 2019July 13, 2019

Deconstructing the Mean Value Theorem, Part 2

The Mean Value Theorem says there’s at least one point where the slope of the tangent line on a smooth curve equals the slope of the secant line between the endpoints.

At its heart, the Mean Value Theorem is fairly intuitive. It essentially states that a smooth curve has at least one tangent line whose slope is equal to the

… Read the rest