The tutor explains the difference between power and exponential curves. According to Excel, a power equation has the form y=axb whereas an exponential equation has the form y=aekx Example: I tried both options on the following data: x y 0.5 …

Spreadsheets: regression curves: power vs exponential Read more »

The tutor shows how to get a best-fit line using Excel or LibreOffice Calc. Let’s imagine you want a best fit line of form y=mx + b for the following data: x y 0 3 2 5 6 10 8 …

Spreadsheets: linear regression in four easy steps on Excel or LibreOffice Calc Read more »

The tutor tells a trick for printing long strings with JavaScript. Suppose you have a long string, over many lines, that you want to print with JavaScript. Typically, to print a string, you might assign it to a variable, then …

Web Programming: JavaScript: how to manage a multi-line string Read more »

The tutor shows an example of a wrapper program in action. To my knowledge, a wrapper is a program that hides a function that the managing system can’t handle. The “wrapping” is code that the managing system recognizes as the …

Web design: a JavaScript wrapper for SVG in WordPress Read more »

The tutor gives an example to show that with matrices, AB=AC doesn’t mean B=C. Consider the matrices A, B, C, and D: By matrix multiplication, AB=AC. (In fact, both products equal D.) Yet, obviously, B≠C. Matrix multiplication lacks the cancellation …

Linear algebra: matrix multiplication: no cancellation rule Read more »

The tutor explains concavity and point of inflection with an example. Concavity refers to an aspect of graph shape. My first-year calculus professor explained it this way: concave upward will collect rain, while concave downward will shed rain. Numerically, when …

Calculus: concavity and point of inflection Read more »