Archive for the ‘Mnemonics’ Category

Hyperbolic Mnemonic

Friday, 11 October 2013

If you have problems remembering which is which with sinh and cosh, or their graphs, or which way around their definitions are:

\sinh x = \dfrac{\mathrm{e}^x - \mathrm{e}^{-x}}{2}

\cosh x = \dfrac{\mathrm{e}^x + \mathrm{e}^{-x}}{2}

then it might help if you notice that the graph of sinh is somewhat S-shaped (though backwards), and cosh is C-shaped (though open upwards).

[Well, unless you’re Russian, where the Cyrillic letter Es (‘С’) corresponds to our ‘S’; that might throw a graphemic spanner in the works.]


Learning the Multiplication Tables

Tuesday, 21 December 2010

In a previous post, I tried to show that learning the multiplication tables need not be daunting for children (or even adults). Here are a few odd methods and techniques that might also help.


Colour Mixing

Sunday, 26 April 2009

There seems to be some confusion about what the primary and secondary colours are. Well, it depends.


Dimensional Analysis of the Kinematic Equations

Sunday, 26 April 2009

To help to remember the kinematic equations, it may be useful to know a little dimensional analysis.


Planetary Mnemonic

Tuesday, 21 April 2009

Here’s something I noticed that might help people to remember the order of some of the planets – mainly the gas giants.

Beyond Mars are:

  • Jupiter
  • Saturn
  • Uranus
  • Neptune

notice the initial letters in the order SUN away from the Sun.

Dimensional Analysis of Statistical Formulae

Monday, 20 April 2009

Dimensional analysis (also used in Physics) can be used to check statistical formulae.


Trigonometric Mnemonic

Wednesday, 8 April 2009

At school we had a saying with which to remember the trigonometric forms:

  • \sin(\vartheta) = O/H
  • \cos(\vartheta) = A/H, and
  • \tan(\vartheta) = O/A

in a right-angled triangle, where

  • \vartheta is one of the other angles
  • O is the short side opposite the angle
  • A is the short side adjacent to the angle, and
  • H is the hypotenuse (the long side).

The saying was

Some Old Horses
Can Always Hear
Their Owners Approach.

Possessive Apostrophes

Tuesday, 7 April 2009

There’s a very easy rule for using apostrophes to indicate possession.