The tutor tells a quick hint about calculations with logs. Although base e log (ln) is often used, some lab scientists prefer base 10 log (aka, common log or simply “log”). Typically, of course, logx is assumed to be base …
Math, chemistry: conversion of natural logarithm (ln) to log base 10 Read more »
The tutor contemplates shifting gears from snow shoveling to lawn mowing. Let’s imagine a lawn 25mx25m, so its area is 625m2, and that the mower covers 0.15m2 every second. At what second during the procedure will the mower cover 1% …
The tutor shows the seriessum() function, found on both Excel and LibreOffice Calc. A geometric series has the form Sn = cr0 + cr1 + … + crn-1 An example is 3 + 3*4 + 3*42 + … + 3*45 …
Spreadsheets: Excel and LibreOffice Calc: the sum of a geometric series Read more »
The tutor reports an interesting statistic. In 2013, the world population was approximately 7.07 billion. At the same time, people aged ≥ 100 numbered about 450 thousand. Those figures suggest that a completely random person on Earth has probability 450 …
Probability, demographics: a person’s chance of reaching age 100 Read more »
The tutor shows the log() function on Excel and LibreOffice Calc. Pretty much every scientific calculator has log and ln keys, with the log base 10, the ln base e. What if you need log base 5, for instance? Of …
The tutor works a word problem to find time until market share equalization. Imagine a relatively new device, of which there are two competing versions, A and B. (We assume that no-one owns both.) The potential market is 100 million, …
Business math: a word problem about market share. Read more »
The tutor shows how to get a best-fit line with the HP-10B. Imagine the following data: x y 3 10.1 4 14.7 9 32.5 12 47.1 To get a best-fit line for it of form y=mx+b, here are the steps: …
The tutor looks at forming a Taylor polynomial with the example of square root 31. A transcendental function is one there is no operation for. Rather, it’s represented by a series of expressions. Square root and sin are two examples. …
Math: evaluating transcendental functions: Taylor polynomial for square root Read more »
The tutor shares a discovery about the Casio fx-260Solar. The Casio fx-260Solar is a great calculator. Of course, it’s reverse entry for square root, sin, cos, tan, etc, so might be a little less popular with some people. When you …
Math: Calculator usage: brackets on the Casio fx-260Solar Read more »
The tutor prepares for a statistics experiment. The first step is to generate two lists: one random, one less so. To generate fifteen random numbers with Perl one can use the following code: for ($i=0;$i