## The slide rule is a mechanical analog computer.

The rulers each have a logarithmic scale(the spacing between the lines on the scale become smaller as the value increases), it is possible to align them to calculate the product of two numbers.

### The Slide Rule

**Cursor**is a glass indicator.**Black scales**increase from left to right.`C`

&`D`

scales are single (1-10) scales.`A`

&`B`

scales are double (1-10-100) having two cycles`K`

is triple (1-10-100-1000) having three cycles**Red scales**increase from right to left.`CI`

&`DI`

scales are single (1-10) scales.**Trig scales**increase from right to left.`S`

&`T`

scales.

I am using a Hemmi Bamboo with `A`

, `B`

, `CI`

, `C`

, `D`

, `K`

, `S`

& `T`

.

### Multiplication

2.2 × 3.5

- Slide
`C`

**rightward**, to align its 1 over 2.2 on`D`

. - Slide the cursor to 3.5, the result will be on
`D`

as 7.7.

3.2 × 4.6

Trying to slide the cursor toward 4.6 will reach the end of the scale, we must use the inverted `CI`

scale.

- Slide
`CI`

**leftward**, to align its 1 over 3.2 on`D`

. - Slide the cursor to 4.6, the result will be on
`D`

as 1.47, mul 10.

### Division

3.2 / 4.6

- Slide cursor to 3.2 on
`D`

. - Slide
`C`

**leftward**to 4.6 to align with cursor. - Slide cursor to nearest 1 on
`C`

, the result will be`D`

as 6.9, div 10.

### Square

4.0^{2}

- Slide cursor to 4.0 on
`C`

. - The result will be on
`B`

as 16.

### Sin

sin(25)

- Slide to 25 on
`S`

, on the backface on Hemmi Bamboo. - The result will be on
`B`

as 42.

### Reference

`A` | x^{2} | square | 1 to 100 | On body. Two log cycles at half the scale of C/D. |

`B` | x^{2} | square | 1 to 100 | On slider. Two log cycles at half the scale of C/D. |

`CI` | 1/x | reciprocal C | 1/0.1 to 1/1.0 | On slider. C scale in reverse direction. |

`C` | x | fundamental scale | 1 to 10 | On slider. |

`D` | x | fundamental scale | 1 to 10 | On body. |

`K` | x^{3} | cube | 1 to 1000 | Three cycles at one third the scale of D. |

`S` | sin(x) | sin | sin(5.74°) to sin(90°) | On backface, above. |

`T` | tan(x) | tangent | tan(45°) to tan(84.3°) | On backface, below. |

**Incoming**: paper computing