Digital Slide Rule vs GraphMath

The slide rule was used for over 400 years as a calculating/estimation tool. Abandoned with the advent of hand-held calculators, computers and smart phones, their elegant simplicity is still a thing of wonderment. This program replicates the most common types of slide rules: Straight, circular, spiral and cylindrical. Dozens of scales are included and numerous features that could never exist on a physical slide rule are also included, such as color options, numeric displays of the values under the hairlines, and so on. Slide rules were used to go to the moon and to build bridges, skyscrapers, tunnels, aqueducts and nearly everything else. Slide rules were simple to use and accurate enough for most occasions. Also, note that this program is processor-intensive and with heavy use, will probably drain your battery quickly. Every effort has been make the program efficient, but nevertheless, some functions take a few moments to occur, including initial load, which can take three or four seconds, or perhaps a little longer. Nearly 30,000 "nibs" are created during this time, as well as over 3,000 labels, so please be a little patient! Because of all the detail, it looks best and runs best on a large-format machine such as a tablet. Also because of all the detail, the 30-loop spiral slide rule converts to a low-rez "bitmap data image" while you move it, then back to a "vector based image" as soon as you release. Includes a brief side show slide show of famous and interesting slide rules, most of which are in the author's collection. Two are public-domain photographs of antique slide rules. --------------------------------------------------------- Notes on usage: Program features include "two-finger pinch/zoom." Slide rule slide show images can also be rotated. Enlarge an image by double-tapping in the same place. Tapping three times in the same place will return the program to the home position. Tapping four times will bring up an intro-screen message which requires tapping anywhere to remove. ---------------------------------------------------------- This program was first released in 2016 and is the product of a lifelong love of numbers (and 30+ years of programming experience!). Special thanks to the Oughtred Society for their member's invaluable help in evaluating the earliest versions of this program.

This graphing calculator is user friendly and powerful.  It is fully compatible with iOS 14 and 15, and mostly compatible with iOS 13 and Mac OS. Cartesian 3D Z = F (X, Y) functions:  ——————————————————— Graphs can be:  1. Drawn as surface, lines, or dots. 2. Drawn with or without perspective, and with different light and reflection settings. 3. Tilted up or down. 4. Rotated to any position. 5. Drawing is animated by either X, Y, or Z. Table of all points can be sorted by either X or Y. Cylindrical 3D Z = F (Θ, R) functions:  ——————————————————— Graphs can be:  1. Drawn as surface, lines, or dots. 2. Drawn with or without perspective, and with different light and reflection settings. 3. Tilted up or down. 4. Rotated to any position. 5. Drawing is animated by Θ, R, or Z. Table of all points can be sorted by either Θ or R. Spherical 3D R = F (Θ, Φ) functions:  ——————————————————— Graphs can be:  1. Drawn as surface, lines, or dots. 2. Drawn with or without perspective, and with different light and reflection settings. 3. Tilted up or down. 4. Rotated to any position. 5. Drawing is animated by either Θ or Φ. Table of all points can be sorted by Θ, Φ, or R. Cartesian 2D Y = F (X) functions:  ———————————————— Graph displays the following curves: 1. One or two Y = F (X) functions. 2. Derivative of the first function. 3. Integral of the first function as a shade and a curve.  Graph features:  1. Drawing is animated by X. 2. Clicking on the curves shows curve values, and finds closest point in the table. Tables: 1.  All function, integral, and derivative values. 2.  Zero intersections of first function. 3.  Intersections between first and second functions. Polar 2D R = F (Θ) functions: ———————————————  Graph displays the following curves: 1. One or two R = F (Θ) functions. 2. Integral of the first function as a shade and a curve. Graph features:  1. Drawing is animated by Θ.  2. Clicking on the curves shows curve values, and finds closest point in the table. Tables: 1.  Table of all function and integral values  2.  Table of zero intersections of first function. 3.  Table of intersections between first and second functions. Parametric 2D X = F1 (T), Y = F2 (T) functions: —————————————————————————  Graph features:  1. Drawing is animated by T.  2. Clicking on the curves shows T, X, and Y values, and finds them in the table. Table of all points. F (X, Y) = 0  equations: ———————————— Graph displays solutions as points. Clicking on the points shows X, and Y values, and finds them in the table. Table of all points. Common features: —————————— 1. List of previous entries. 2. List of preset entries. 3. Undo and redo buttons for formula entries. 4. Automatic correction of errors in function limits or steps are offered. 5. All function points can be saved to clipboard in a table format. 6. All function points can be displayed on corresponding graphs. 7. Control colors can be changed to black and white. 8. Link to Vectors and Planes 3D Geometry Guide App. 9. Link to Matrix Calculator Step by Step App. Common features of all images:  1. Animation frames can be frozen and moved back or forward. 2. Animation speed can be adjusted. 3. Zoom. 4. Scroll. 5. Save to Clipboard. 6. Save to Photos 7. Color picker. New functions and further UI improvements for our apps are coming! Developers hope to get feedback at graphmath@aol.com.