Fun with a Slide Rule app for iPhone and iPad

The ARK Apps Slide Rule app simulates a physical slide rule. It has ten menu options:

1. Multiplication using the A and B scales.
2. Division using the A and B scales.
3. Multiplication using the C and D scales.
4. Division using the C and D scales.
5. Squares and square roots using the A and D scales.
6. Cubes and cube roots using D and K scales.
7. Sines and cosines of angles from 6 to 80 degrees using the C and S scales.
8. Tangents and cotangents of angles from 6 to 45 degrees using the C and T scales.
9. Logarithms of numbers using the C and L scales.
10. A note about slide rules.

When an option is selected the slide rule hides any scales which are not relevant to the operation.

The app uses pan gestures to move the middle rule and the cursor. The top and bottom rules are fixed just like a physical slide rule.

The app illustrates the principles behind the numerical operations and gives an insight into why slide rules were widely used by scientists, engineers, architects etc before the advent of the modern calculator.