Handy Facts - Mathematics
Prefixes
| Prefix | Abbr | Exponent of 10 |
|---|
| yocto | y | -24 |
| zepto | z | -21 |
| atto | a | -18 |
| femto | f | -15 |
| pico | p | -12 |
| nano | n | -9 |
| micro | µ | -6 |
| milli | m | -3 |
| centi | c | -2 |
| deci | d | -1 |
|
| deka | da | 1 |
| hecto | h | 2 |
| kilo | k | 3 |
| mega | M | 6 |
| giga | G | 9 |
| tera | T | 12 |
| peta | P | 15 |
| exa | E | 18 |
| zetta | Z | 21 |
| yotta | Y | 24 |
Constants
- sqrt(2) - square root of 2
- 1.41421 35623 73095 04880 16887
- phi = 1/2(sqrt(5)+1)
- 1.61803 39887 49894 84820 45868 34365
- sqrt(3) - square root of 3
- 1.73205 08075 68877 29352 74463
- e
- 2.71828 18284 59045 23536 02874 71352
- pi
- 3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37511
Trigonometry
| sin | y / r | | csc | r / y |
| cos | x / r | | sec | r / x |
| tan | y / x | | cot | x / y |
If you remember the little jingle "sine, cosine, tangent;
cosecant, secant, cotangent", and that you begin with 'y',
then you can fill out the above table from memory any time you
need to do any trig. Just put the trig functions down in a 2x3 table,
and then, beginning with 'y', fill in the fractions: y / r, then x / r
below it, then because you've got y on the top of the first row and
x on the top of the second row, then the third row is y / x.
The other column is the reciprocal of the first.
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