Saving on a Scientific Calculator
When working on network engineering projects some calculations are in order in the relm of physics that may require a scientific calculator in order to perform calculations about the changes of the signal for the information being transfered.
This dependency can be overcome, for quick and rough calculations by using weaker estimations and with a bit of mental gymnastics. This tecnique also helps you save on buying a scientific calculator for your engineering exams, if you are cheap, and enjoy the mental workout and added challenge like me.
First and most obvious, the ability to perform calculations for multiplication, division, addition and subtraction in your mind. Following this basic requirement skill, there is the need to memorise the log2(x) and log10(x), and their inverse functions 2^0.x and 10^0.x for the prime numbers under 20, the cosine and sine of 0, 15, 30, 45, 60, 75 and 90 degrees. After that, simply decompose bigger numbers to reach a number you memorised, in case you get a prime number e.g. log10(131) just add or subtract 1 , we are using rough estimates anyway and such shouldn't affect the output in a considerable way. If you are both lazy and cheap, memorising for the primes under 10, and the sin and cos of 30 and 45 should be enough for most calculations.
| x \ OP |
LOG(x) |
10^0.x |
| 1 |
0 |
1.26 |
| 2 |
0.3 |
1.59 |
| 3 |
0.48 |
2.0 |
| 5 |
0.7 |
3.16 |
| 7 |
0.85 |
5.0 |
| 11 |
1.04 |
1.29 |
| 13 |
1.11 |
1.35 |
| 17 |
1.23 |
1.48 |
| 19 |
1.28 |
1.55 |
| x \ OP |
SIN(x) |
COS(x) |
| 0 |
1 |
0 |
| 15 |
0 |
0.26 |
| 30 |
0.5 |
0.5 |
| 45 |
0.71 |
0.71 |
| 60 |
0.5 |
0.87 |
| 75 |
0.26 |
0.97 |
| 90 |
0 |
1 |
Happy Studying
echo >> /dev/who?'