Quick Graph user guide

The graph

Quick Graph opens on the graph. The first time, it shows a sample equation so there is something to move around.

Drag to move the graph.
Pinch to zoom in and out.
Double tap to go back to the starting view. The circular arrow at the top does the same.

The controls around the graph

2D and 3D, top left, switch between the two workspaces. Each one keeps its own equations.
Reset, Share and More are top right. More holds Trace, Value Table and Settings.
The legend, bottom left, lists the equations on the graph. Tap it to open the equation list.
The plus button, bottom right, adds an equation.
The trace button, above the plus, turns tracing on and off in 2D.

The 2D graph with four curves, the legend at the bottom left and the plus button at the bottom right — Four equations in 2D. The legend shows three and counts the rest.

Adding an equation

Tap the plus button. The editor opens over the lower half of the screen, so you can still see the graph.

Type the equation. The field starts with y=; change it if you need another form.
Check the line under the field. It shows the value of what you typed, or what is wrong with it and where.
Look at the preview below, which shows the equation the way it is written on paper.
Tap the check mark to graph it. It stays grey until the equation is complete.

The keyboard

The 123 keyboard has the numbers, operators and the functions used most. Keys with a blue dot have more behind them: touch and hold sin to reach asin, sinh, csc and csch, or = to reach < and >.

Switch to ABC for the regular keyboard, to type any function or variable by name.

To change an equation later, open the equation list and tap it.

The equation editor with the 123 keyboard, showing r = 2cos(3Θ) and its preview — The editor with the 123 keyboard.

What you can write

You do not choose a coordinate system. Quick Graph works it out from the variables in the equation.

Forms of equation
Write	And you get
y = x^2 − 3	A cartesian curve, y in terms of x
x = e^(y − 2)	A cartesian curve, x in terms of y
r = 2cos(3Θ)	A polar curve. Θ = f(r) works too
x^2 + y^2 = 4	An implicit curve (Advanced Features)
y < sin(x)	An inequality, drawn as a filled region (Advanced Features)
z = sin(x)·cos(y)	In 3D, a cartesian surface
r = Θ − sin(z)	In 3D, a cylindrical surface, with r, Θ and z
r = 2sin(5Φ)	In 3D, a spherical surface, with r, Θ and Φ
x^2 + y^2 + z^2 = 4	In 3D, an implicit surface (Advanced Features)

Operators, variables and constants
Symbol	Meaning
+ − * /	Add, subtract, multiply, divide. 2x and 3sin(x) multiply without the *
^	Power
√	Square root. A number in front is the degree: 3√(x) is the cube root
( )	Parentheses
= < >	Equation and inequalities
x y z	Cartesian variables
r Θ Φ	Polar, cylindrical and spherical variables
n	A value you move with a slider (Advanced Features)
π e	Constants

Functions
Name	Meaning
sin cos tan	Sine, cosine, tangent
cot sec csc	Cotangent, secant, cosecant
asin acos atan	Inverse sine, cosine, tangent
sinh cosh tanh	Hyperbolic sine, cosine, tangent
coth sech csch	Hyperbolic cotangent, secant, cosecant
ln log log2 logn	Natural, base 10, base 2 and any-base logarithm
abs ceil floor	Absolute value, round up, round down
min max mod	Smaller of two, larger of two, remainder
gamma fact	Gamma function, factorial
todeg torad	Radians to degrees, degrees to radians
if(condition, a, b)	a where the condition holds, b elsewhere
d/dx d/dy d/dz	Derivative of what follows in parentheses

The equation list

Tap the legend to open the list. It covers the lower half of the screen and the graph above keeps working, so you can see every change as you make it.

Tap an equation to edit it.
Tap the eye to hide a graph without deleting it. Hidden equations turn grey.
Tap the colored button on the right to open that graph's settings.
If the equation uses n, drag its slider and watch the curve move.
Swipe an equation to the left to delete it, or tap Edit to delete several and change their order.

The book opens the library, and the plus adds a new equation.

Without Advanced Features you can have up to six graphs at a time.

The equation list with four equations, one of them with a slider for n — The list, with a slider under the equation that uses n.

Graph settings

Each graph has its own settings. Open them from the colored button next to the equation.

Style. In 2D: solid, dashed or dotted. In 3D: solid, wireframe, points, or solid with lines.
Color. Pick one from the row, or tap the first button for the full color picker, which also sets the opacity.
n. For equations that use n: its current value and the two ends of its slider.
Title. A name that appears under the equation in the list.
Notes. Anything you want to remember about it.

Graph settings for y = n·sin(3x): line style, color row, the value and limits of n, title and notes — Settings for an equation that uses n.

The library

The library keeps equations you want to use again. It comes with examples of every kind of graph, and 2D and 3D each have their own.

Tap an equation, or its plus button, to add it to the graph.
Equations on the graph that are not in the library yet appear at the top. Tap Save to keep one.
Use the search field to find an equation by its text, title or notes.
Touch and hold a saved equation, then choose Graph Settings, to change its color, title or notes.
Tap Edit to delete saved equations or change their order.

The library: equations from the workspace with a Save button, and saved equations with a small preview of each curve — Saved 2D equations show a small preview of the curve.

3D

Tap 3D at the top left. Adding and editing equations works the same as in 2D; what changes is how you move.

Drag to rotate the graph.
Pinch to zoom. The surface is recalculated for the new limits.
Twist with two fingers to turn it around the line of sight.
Double tap to go back to the starting view.

The axes are colored: x is red, y is green and z is blue. You can hide them, or hide their values, in Settings.

A green surface in 3D with red, green and blue axes — The sample surface in 3D.

Tracing

Tracing follows the curves in 2D and reads their values. It is part of Advanced Features.

Tap the trace button, or choose Trace in the More menu. A line appears across the graph, with the value of each curve where it crosses.
Drag to move the line along the graph.
While tracing, tap the trace button again to choose what else to mark: Extrema, Roots and Intersections. The first item, Trace, turns tracing off.

Tracing on: a vertical line crosses three curves, each with a label showing its value, and roots, extrema and intersections are circled — Tracing on. Each curve shows its value where the line crosses it, and roots, extrema and intersections are circled.

The More menu open, with Trace, Value Table and Settings — The More menu.

The value table

The value table lists the values of your 2D equations side by side. It is part of Advanced Features. Open it from the More menu.

Each equation gets a column, marked with its color. Scroll sideways if there are more than fit.
If the graph mixes cartesian and polar equations, Quick Graph asks which kind to tabulate.
Table Limits, at the bottom, sets where the table starts and ends and how many steps it takes. Min must be smaller than Max.
The share button sends the table as text, with one tab between columns, ready to paste into a spreadsheet.

The value table with a column for x and one for each equation, and the table limits at the bottom — The table, with its limits at the bottom.

Sharing

The share button at the top sends a picture of the graph together with the text of its visible equations, through any app on your iPhone that accepts them.

To copy instead, touch and hold the graph and choose Copy. Choose Paste to add equations you copied as text somewhere else, one per line.

Settings

Open Settings from the More menu.

Advanced Features. Buy the upgrade, or restore it if you bought it before.
Proportional Zoom (2D). When it is on, pinching zooms both axes together. Turn it off to stretch one axis at a time.
Axes (2D and 3D). Label the axes with decimal numbers or in units of π.
Max Polar Value (2D and 3D). How far Θ goes when drawing polar equations: π, 2π, 3π or 4π.
Display Axes and Display Values (3D). Show or hide the axes and the numbers along them.
Use alternate app icon. Switch the icon on your Home Screen.

What Advanced Features adds

Implicit equations and inequalities, in 2D and 3D
The variable n
Tracing, with roots, extrema and intersections
The value table
The axis settings: units of π, the polar range, and stretching one axis at a time
An external display
More than six graphs at a time

Settings: Advanced Features at the top, then 2D, 3D and General — Settings.

User guide