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SECTIONFunctions15 subsectionsBROWSE ALL ↓INTERACTIVE1 TOOLFunctions VisualTools11 toolsJump to ↓fREFERENCE65 ITEMSfFunctions FormulasReference38 itemsJump to ↓AaFunctions Termsand Definitions27 itemsJump to ↓§CORE TOPICS12 SUBSECTIONSAnalyzing FunctionsJump to ↓Function Arithmetic:Operations on FunctionsJump to ↓Functions BasicsJump to ↓Function CompositionJump to ↓Domain of a FunctionJump to ↓Function FamiliesJump to ↓Graphs of FunctionsJump to ↓Inverse FunctionsJump to ↓Piecewise FunctionsJump to ↓Properties of FunctionsJump to ↓Range of a FunctionJump to ↓Function TransformationsJump to ↓

Functions Visual Tools

11 toolsExplore Functions Visual Tools
Interactive explorers for how functions behave: domain and range, graphs and asymptotes, symmetry and reflections, transformations, composition, inverse functions, piecewise definitions, tangent lines, and function types — each tool animated and adjustable so the algebra and the picture stay connected.
Visual Tool

Function Asymptotes Visualizer

Find vertical, horizontal, and oblique asymptotes of common functions and watch them drawn as color-coded dashed lines over the curve. One-sided limit probes report whether each vertical asymptote tends to plus or minus infinity from each side, and four transformation sliders let you watch every asymptote track shifts and scales in real time.

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Visual Tool

Function Composition Visualizer

Pick an outer function f and an inner function g from ten base families to see both compositions plotted on the same graph — f composed with g in blue, g composed with f in amber. The visual contrast makes it immediate that composition is not commutative, while live symbolic expressions and special-case notes for identity and inverse pairs build the intuition behind f of g of x.

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Visual Tool

The Domain Card and Applied Chips

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Visual Tool

Inverse Function Visualizer

Plot any function alongside its inverse as a reflection across the line y = x. Pick a base function — linear, cubic, reciprocal, exponential, logarithmic, square root, quadratic, absolute, sine, or cosine — apply affine transformations, and watch the inverse re-derived symbolically in real time. For functions that need a domain restriction to be invertible, the discarded portion appears faded and the principal branch in bold.

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Piecewise Function Builder

Build piecewise functions piece by piece — pick a shape from a catalog, set each piece

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Range of a Function Visualizer

See the set of achievable outputs of any function drawn directly on the y-axis as a colored band, with a horizontal number line below the plot and a draggable test point that checks whether any specific y-value is reached. Pick from eleven base functions grouped by range shape and watch the range respond live to vertical scale and shift — while horizontal transformations leave it unchanged.

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Visual Tool

Function Reflections Visualizer

Pick a base function — linear, quadratic, cubic, reciprocal, exponential, logarithmic, sine, cosine, absolute value, or square root — and switch between seven reflection types: across the x-axis, y-axis, y = x, the horizontal y = c, the vertical x = c, plus |f(x)| and f(|x|). Both curves draw together, with the axis of reflection highlighted in orange.

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Visual Tool

Function Symmetry Visualizer

See whether any function is even, odd, or neither by plotting f(x) alongside its y-axis reflection f(-x) and its origin rotation -f(-x) on one graph. Overlapping curves prove the symmetry visually, a color-coded verdict card states the result, and a step-by-step algebraic derivation walks through the test. Transformation sliders let you watch shifts break even or odd symmetry in real time.

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Visual Tool

Tangent Line Visualizer

Drag the x₀ slider and watch the tangent line follow the curve in real time. Pick a base function — linear, quadratic, cubic, reciprocal, exponential, logarithmic, square root, absolute, sine, cosine — apply affine transformations, and read both the point-slope and slope-intercept forms of the tangent equation alongside the slope m = f

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Functions Formulas Reference

38 itemsSee All Functions Formulas Reference
This reference collects 38 function formulas organized into 9 categories - the standard toolkit for working with functions across precalculus and into calculus.

Function Arithmetic covers pointwise sum, difference, product, and quotient along with the domain rules for combined and quotient functions. Composition covers chaining functions, the domain of a composite, associativity, and the inverse of a composition. Inverse Functions covers the defining input-output swap, the verification by composition, the inverse of an inverse, and the domain-range exchange. Symmetry gives the algebraic tests for even and odd functions. Transformations collects the master form together with vertical and horizontal translations, reflections, and dilations. Linear Function Forms and Quadratic Function Forms provide the multiple equivalent representations of these two function families, with the slope formula and perpendicular-slope condition. Asymptotes covers vertical and horizontal asymptotes of rational functions. Rates of Change closes the set with the average rate of change and the difference quotient - the bridge to derivatives.

Each entry shows the formula in LaTeX, an explanation of what the formula captures, and where applicable a derivation, conditions for validity, common variants, and links to related formulas and definitions.
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Functions Terms and Definitions

27 itemsSee All Functions Terms and Definitions
Complete glossary of function terms with definitions and examples. Covers domain, range, function types, composition, inverses, and graph transformations.
Core Concepts6
FunctionA rule that assigns exactly one output to each input. Formally, a function ff from set AA to set BB is a mapping f:AoBf: A o B such that every…Read more →RelationAny set of ordered pairs — a collection of input-output associations with no restriction on how many outputs an input may have.Read more →DomainThe set of all inputs for which a function produces a valid output: Dom(f)={xf(x) is defined}\text{Dom}(f) = \{x \mid f(x) \text{ is defined}\}.Read more →RangeThe set of all output values a function actually produces as the input varies across the entire domain:…Read more →Independent VariableThe input variable of a function, whose value is chosen freely from the domain.Read more →Dependent VariableThe output variable of a function, whose value is determined by the input through the function rule.Read more →
One-to-One FunctionA function where distinct inputs always produce distinct outputs: f(a)=f(b)impliesa=bf(a) = f(b) implies a = b.Read more →Even FunctionA function satisfying f(x)=f(x)f(-x) = f(x) for all xx in its domain.Read more →Odd FunctionA function satisfying f(x)=f(x)f(-x) = -f(x) for all xx in its domain.Read more →Increasing FunctionA function is increasing on an interval if a<b    f(a)<f(b)a < b \implies f(a) < f(b) for all a,ba, b in that interval.Read more →Decreasing FunctionA function is decreasing on an interval if a<b    f(a)>f(b)a < b \implies f(a) > f(b) for all a,ba, b in that interval.Read more →Piecewise FunctionA function defined by multiple formulas, each applying to a different subset of the domain.Read more →
Parent FunctionThe simplest function in a family — the baseline shape with no transformations applied.Read more →Linear FunctionA function of the form f(x)=mx+bf(x) = mx + b, where mm is the slope and bb is the yy-intercept.Read more →Quadratic FunctionA function of the form f(x)=ax2+bx+cf(x) = ax^2 + bx + c with $a
eq 0$. The graph is a parabola.
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Constant FunctionA function of the form f(x)=cf(x) = c where cc is a fixed real number. Every input produces the same output.Read more →Absolute Value FunctionThe function f(x)=xf(x) = |x|, returning the distance of xx from zero: x={xif x0 xif x<0|x| = \begin{cases} x & \text{if } x \geq 0 \ -x & \text{if } x < 0 \end{cases}.Read more →
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Analyzing Functions

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Learn function analysis by identifying intervals of increase and decrease, local extrema, end behavior, symmetry, and positive and negative intervals from graphs.
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Function Arithmetic: Operations on Functions

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Learn function arithmetic: adding, subtracting, multiplying, and dividing functions. Master combined function domains, sum of functions, quotient of functions, and real-world applications.
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Functions Basics

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The complete first course in functions on one page: what a function is and the uniqueness rule that defines it, functions versus relations, the vertical line test, notation and evaluation, the four ways to represent a function, independent and dependent variables, special values, real-world context, and a guided map of every function topic in the section.
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Function Composition

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Master function composition with step-by-step examples. Learn to evaluate composite functions, find composite function domains, and decompose complex functions.
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Domain of a Function

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Learn how to find the domain of any function including rational, radical, logarithmic, and composite functions. Step-by-step methods with interval notation examples.
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Function Families

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Learn all major function families including linear, quadratic, exponential, logarithmic, rational, and radical functions. Explore their graphs, properties, and how to identify each type.
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Graphs of Functions

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Learn how to graph and analyze functions. Covers the coordinate plane, plotting techniques, intercepts, key features, types of curves, and graph interpretation.
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Inverse Functions

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Learn inverse functions: how to find, graph, and verify them using algebraic steps, the horizontal line test, and domain-range swaps with clear examples.
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Piecewise Functions

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Learn how to define, evaluate, and graph piecewise functions. Step-by-step examples covering notation, continuity, and real-world applications of piecewise-defined functions.
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Properties of Functions

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Learn properties of functions: even and odd symmetry, one-to-one, monotonicity, continuity, asymptotes, end behavior, extrema, zeros, concavity, and more.
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Range of a Function

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Learn what the range of a function is and how to find it using algebraic and graphical methods. Covers interval notation, common functions, transformations, and invertibility.
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Function Transformations

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Learn function transformations including vertical and horizontal shifts, reflections, stretches, and compressions. Master graphing techniques and writing equations from graphs.
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