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🥭AP Pre-Calculus Unit 2 Vocabulary

173 essential vocabulary terms and definitions for Unit 2 – Exponential and Logarithmic Functions

Study Unit 2
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🥭Unit 2 – Exponential and Logarithmic Functions
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🥭Unit 2 – Exponential and Logarithmic Functions

2.10 Inverses of Exponential Functions

TermDefinition
baseThe number b in exponential functions b^x or logarithmic functions log_b x, where b > 0 and b ≠ 1.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
exponential growthA pattern of change where output values increase multiplicatively as input values increase additively.
identity functionThe function h(x) = x, which serves as the line of reflection between inverse exponential and logarithmic functions.
inverse functionA function that reverses the mapping of another function, such that if f(x) = y, then f⁻¹(y) = x.
inverse relationshipA relationship between two functions where the input and output values are reversed, such that one function undoes the other.
logarithmic functionA function of the form f(x) = a log_b x where b > 0, b ≠ 1, and a ≠ 0, characterized by output values changing additively as input values change multiplicatively.
logarithmic growthA pattern of change where output values increase additively as input values increase multiplicatively.
ordered pairA pair of values (x, y) representing a point on a graph or a relationship between input and output values.
reflectionA transformation that flips a graph over a line, such as the line y = x.

2.1 Change in Arithmetic and Geometric Sequences

TermDefinition
arithmetic sequenceA sequence where each term after the first is found by adding a fixed number called the common difference to the previous term.
common differenceThe constant difference between successive terms in an arithmetic sequence, denoted by d.
common ratioThe constant factor by which each term in a geometric sequence is multiplied to obtain the next term.
constant proportional changeA relationship where successive terms change by the same multiplicative factor, characteristic of geometric sequences.
constant rate of changeThe uniform change between successive terms in an arithmetic sequence.
general termA formula that represents any term in a sequence based on its position, such as g_n = g_0 r^n for geometric sequences.
geometric sequenceA sequence where each term after the first is found by multiplying the previous term by a fixed number called the common ratio.
initial valueThe starting value of a function, represented by b in linear functions and a in exponential functions.
sequenceA function from the whole numbers to the real numbers, producing a list of ordered values.
whole numbersThe set of non-negative integers {0, 1, 2, 3, ...} used as the domain for a sequence function.

2.11 Logarithmic Functions

TermDefinition
additive transformationA transformation of a function involving addition or subtraction, resulting in vertical and horizontal translations.
concave downA characteristic of a graph where the rate of change is decreasing, creating a curve that opens downward.
concave upA characteristic of a graph where the rate of change is increasing, creating a curve that opens upward.
decreasing functionA function over an interval where output values always decrease as input values increase.
domainThe set of all possible input values for which a function is defined.
end behaviorThe behavior of a function as the input values approach positive or negative infinity.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
extremumMaximum or minimum points on a function; logarithmic functions do not have extrema except on closed intervals.
increasing functionA function over an interval where output values always increase as input values increase.
inverse functionA function that reverses the mapping of another function, such that if f(x) = y, then f⁻¹(y) = x.
logarithmic functionA function of the form f(x) = a log_b x where b > 0, b ≠ 1, and a ≠ 0, characterized by output values changing additively as input values change multiplicatively.
point of inflectionA point on the graph of a polynomial where the concavity changes from concave up to concave down or vice versa, occurring where the rate of change changes from increasing to decreasing or decreasing to increasing.
rangeThe set of all possible output values that a function can produce.
vertical asymptoteA vertical line x = a where the graph of a rational function approaches infinity or negative infinity as the input approaches a.

2.12 Logarithmic Function Manipulation

TermDefinition
change of base propertyThe logarithmic property stating that log_b x = (log_a x)/(log_a b), which allows conversion between logarithms of different bases.
horizontal dilationA transformation that stretches or compresses the graph of a function horizontally by multiplying the input by a constant factor b, written as g(x) = f(bx).
logarithmic expressionsMathematical expressions involving logarithms that can be rewritten in different equivalent forms.
natural logarithmThe logarithmic function with base e, denoted ln(x), that is particularly useful for modeling real-world phenomena.
power property for logarithmsThe logarithmic property stating that log_b x^n = n log_b x, which allows exponents inside a logarithm to be written as coefficients.
product property for logarithmsThe logarithmic property stating that log_b(xy) = log_b x + log_b y, which allows products inside a logarithm to be written as sums.
vertical dilationA transformation that stretches or compresses the graph of a function vertically by multiplying the function by a constant factor a, written as g(x) = af(x).
vertical translationA transformation that shifts the graph of a function up or down by adding a constant k to the function, written as g(x) = f(x) + k.

2.13 Exponential and Logarithmic Equations and Inequalities

TermDefinition
additive transformationsShifts of a function's graph vertically or horizontally, represented by the parameters h and k in transformed function forms.
exponential equationsEquations in which the variable appears in the exponent, solved using properties of exponents and logarithms.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
exponential inequalitiesInequalities in which the variable appears in the exponent, solved using properties of exponents and logarithms.
extraneous solutionsSolutions obtained through algebraic manipulation that do not satisfy the original equation or are excluded by mathematical or contextual limitations.
inverse functionA function that reverses the mapping of another function, such that if f(x) = y, then f⁻¹(y) = x.
inverse operationsOperations that undo each other, such as addition and subtraction or exponentiation and logarithms, used to reverse a function's mapping.
inverse relationship between exponential and logarithmic functionsThe mathematical relationship where exponential and logarithmic functions undo each other, allowing conversion between exponential and logarithmic forms.
logarithmic equationsEquations involving logarithms, solved using properties of logarithms and the inverse relationship with exponential functions.
logarithmic functionA function of the form f(x) = a log_b x where b > 0, b ≠ 1, and a ≠ 0, characterized by output values changing additively as input values change multiplicatively.
logarithmic inequalitiesInequalities involving logarithms, solved using properties of logarithms and the inverse relationship with exponential functions.
properties of exponentsRules governing operations with exponential expressions, used to simplify and solve exponential equations.
properties of logarithmsRules governing operations with logarithmic expressions, including product, quotient, and power properties, used to solve logarithmic equations.

2.14 Logarithmic Function Context and Data Modeling

TermDefinition
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
logarithmic functionA function of the form f(x) = a log_b x where b > 0, b ≠ 1, and a ≠ 0, characterized by output values changing additively as input values change multiplicatively.
logarithmic regressionA statistical method using technology to construct a logarithmic function model that best fits a given data set.
natural logarithmThe logarithmic function with base e, denoted ln(x), that is particularly useful for modeling real-world phenomena.
proportional growthGrowth where input values change proportionally over equal-length output-value intervals, often modeled by logarithmic functions.
real zeroA real number value that makes a polynomial function equal to zero, corresponding to an x-intercept on the graph.
repeated multiplicationA process where an initial value is multiplied by the same proportion multiple times, which can be modeled using logarithmic functions.
transformationChanges applied to a parent function such as translations, reflections, stretches, or compressions.

2.15 Semi-log Plots

TermDefinition
dependent variableThe variable representing output values in a function.
exponential characteristicsProperties of data or functions that follow an exponential pattern, such as constant multiplicative rates of change.
exponential dataData that follows an exponential model of the form y = ab^x, where the rate of change increases or decreases exponentially.
exponential modelA mathematical model of the form y = ab^x that describes data or phenomena exhibiting exponential growth or decay.
initial linear valueThe y-intercept of a linear model on a semi-log plot, which equals log_n a for an exponential model y = ab^x.
linear modelA mathematical representation of a linear relationship, expressed in the form y = mx + b, where m is the slope and b is the y-intercept.
linear rate of changeThe slope of a linear model, representing the constant change in y for each unit change in x; in a semi-log plot of exponential data, this equals log_n b.
linearizationThe process of transforming exponential data into a linear form so that it can be modeled with a linear function.
logarithmically scaledAn axis on a graph where values are marked according to their logarithms, compressing large ranges of data and making exponential functions appear linear.
semi-log graphA graph with a logarithmic scale on one axis and a linear scale on the other axis, used to linearize exponential relationships.
semi-log plotA graph where one axis (typically the y-axis) uses a logarithmic scale while the other axis uses a linear scale, used to visualize exponential relationships.

2.2 Change in Linear and Exponential Functions

TermDefinition
arithmetic sequenceA sequence where each term after the first is found by adding a fixed number called the common difference to the previous term.
common differenceThe constant difference between successive terms in an arithmetic sequence, denoted by d.
common ratioThe constant factor by which each term in a geometric sequence is multiplied to obtain the next term.
constant rateA rate of change that remains the same across all intervals; for quadratic functions, the rate at which average rates of change are changing.
domainThe set of all possible input values for which a function is defined.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
geometric sequenceA sequence where each term after the first is found by multiplying the previous term by a fixed number called the common ratio.
initial valueThe starting value of a function, represented by b in linear functions and a in exponential functions.
linear functionA polynomial function of degree 1 with the form f(x) = mx + b, representing a constant rate of change.
point-slope formA way of expressing linear functions as f(x) = y_i + m(x - x_i) based on a known slope and a point on the line.
proportional changeOutput values that change by a constant factor or ratio over equal-length input intervals, characteristic of exponential functions.
slopeThe rate of change of a line, representing how much the output changes for each unit change in the input.

2.3 Exponential Functions

TermDefinition
additive transformationA transformation of a function involving addition or subtraction, resulting in vertical and horizontal translations.
baseThe number b in exponential functions b^x or logarithmic functions log_b x, where b > 0 and b ≠ 1.
concave downA characteristic of a graph where the rate of change is decreasing, creating a curve that opens downward.
concave upA characteristic of a graph where the rate of change is increasing, creating a curve that opens upward.
domainThe set of all possible input values for which a function is defined.
exponential decayAn exponential function where a > 0 and 0 < b < 1, resulting in output values that decrease as input values increase.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
exponential growthA pattern of change where output values increase multiplicatively as input values increase additively.
extremumMaximum or minimum points on a function; logarithmic functions do not have extrema except on closed intervals.
initial valueThe starting value of a function, represented by b in linear functions and a in exponential functions.
point of inflectionA point on the graph of a polynomial where the concavity changes from concave up to concave down or vice versa, occurring where the rate of change changes from increasing to decreasing or decreasing to increasing.
proportional over equal-length input-value intervalsA characteristic where the ratio of output values remains constant for equal changes in input values, which identifies exponential functions.

2.4 Exponential Function Manipulation

TermDefinition
exponential expressionsMathematical expressions of the form b^x where b is a base and x is an exponent, which can be rewritten in multiple equivalent forms.
exponential unit fractionAn exponent in the form of a unit fraction 1/k where k is a natural number, representing a root of the base.
horizontal dilationA transformation that stretches or compresses the graph of a function horizontally by multiplying the input by a constant factor b, written as g(x) = f(bx).
horizontal translationA transformation that shifts the graph of a function left or right by adding a constant to the input, written as g(x) = f(x + h).
kth rootThe value that, when raised to the power k, equals the base b, represented as b^(1/k).
negative exponent propertyThe rule stating that b^(-n) = 1/b^n, which expresses negative exponents as reciprocals.
power property for exponentsThe rule stating that (b^m)^n = b^(mn), allowing an exponential expression raised to a power to be simplified.
product property for exponentsThe rule stating that b^m · b^n = b^(m+n), allowing products of exponential expressions with the same base to be combined.
vertical dilationA transformation that stretches or compresses the graph of a function vertically by multiplying the function by a constant factor a, written as g(x) = af(x).

2.5 Exponential Function Context and Data Modeling

TermDefinition
baseThe number b in exponential functions b^x or logarithmic functions log_b x, where b > 0 and b ≠ 1.
base of the exponentThe value b in an exponential function f(x) = ab^x that determines the rate at which the function grows or decays.
dependent variableThe variable representing output values in a function.
domainThe set of all possible input values for which a function is defined.
equivalent formsDifferent ways of writing the same mathematical expression that have equal values for all valid inputs.
exponential functionA function of the form f(x) = ab^x where a ≠ 0 is the initial value and b > 0, b ≠ 1 is the base.
exponential modelsMathematical functions of the form f(x) = ab^x used to represent situations where quantities grow or decay by a constant factor over equal intervals.
exponential regressionA statistical method using technology to fit an exponential function model to a data set by finding the best-fitting values for the parameters.
growth factorThe base b in an exponential function f(x) = ab^x, representing the multiplicative change in the output for each unit increase in the input.
initial valueThe starting value of a function, represented by b in linear functions and a in exponential functions.
inputThe independent variable or value that is entered into a function.
natural base eThe mathematical constant approximately equal to 2.718, commonly used as the base in exponential functions that model real-world scenarios.
percent changeThe relative change in a quantity expressed as a percentage, which is related to the growth factor in an exponential model.
proportional growthGrowth where input values change proportionally over equal-length output-value intervals, often modeled by logarithmic functions.
repeated multiplicationA process where an initial value is multiplied by the same proportion multiple times, which can be modeled using logarithmic functions.
transformationChanges applied to a parent function such as translations, reflections, stretches, or compressions.

2.6 Competing Function Model Validation

TermDefinition
data setA collection of numerical values or observations that represent measurements or information about variables.
errorThe difference between a model's predicted value and the actual observed value in a data set.
exponential modelA mathematical model of the form y = ab^x that describes data or phenomena exhibiting exponential growth or decay.
linear modelA mathematical representation of a linear relationship, expressed in the form y = mx + b, where m is the slope and b is the y-intercept.
modelA mathematical representation constructed from a data set to describe relationships or predict values.
overestimateA predicted value that is greater than the actual observed value.
quadratic modelA mathematical representation of a relationship between two variables using a quadratic function of the form f(x) = ax² + bx + c.
rate of changeThe measure of how quickly a function's output changes relative to changes in its input.
regressionA statistical method for fitting a function to a data set to model the relationship between variables.
residual plotA graph displaying the residuals of a regression model, used to assess whether a model is appropriate for a data set.
residualsThe differences between the predicted values from a regression model and the actual observed values in a data set.
underestimateA predicted value that is less than the actual observed value.

2.7 Composition of Functions

TermDefinition
additive transformationA transformation of a function involving addition or subtraction, resulting in vertical and horizontal translations.
analytic representationAn algebraic formula or equation that explicitly defines a function.
commutativeA property where the order of operations does not affect the result; composition of functions is not commutative, meaning f ∘ g typically produces a different result than g ∘ f.
composite functionA function formed by combining two or more functions, where the output of one function becomes the input of another function, denoted as f ∘ g or f(g(x)).
composition of functionsA function operation where one function is applied to the output of another function, written as (f ∘ g)(x) = f(g(x)).
decomposedThe process of breaking down a complex function into simpler component functions that can be composed together.
domainThe set of all possible input values for which a function is defined.
function compositionThe process of combining two or more functions where the output of one function becomes the input of another function.
graphical representationA visual representation of a function displayed on a coordinate plane.
horizontal dilationA transformation that stretches or compresses the graph of a function horizontally by multiplying the input by a constant factor b, written as g(x) = f(bx).
horizontal translationA transformation that shifts the graph of a function left or right by adding a constant to the input, written as g(x) = f(x + h).
identity functionThe function h(x) = x, which serves as the line of reflection between inverse exponential and logarithmic functions.
input valueThe x-values or independent variable values used as inputs to a function.
multiplicative transformationA transformation of a function involving multiplication, resulting in vertical and horizontal dilations.
numerical representationA representation of a function using tables of values or ordered pairs (x, y).
output valueThe y-values or results produced by a function for given input values.
vertical dilationA transformation that stretches or compresses the graph of a function vertically by multiplying the function by a constant factor a, written as g(x) = af(x).
vertical translationA transformation that shifts the graph of a function up or down by adding a constant k to the function, written as g(x) = f(x) + k.

2.8 Inverse Functions

TermDefinition
composite functionA function formed by combining two or more functions, where the output of one function becomes the input of another function, denoted as f ∘ g or f(g(x)).
composition of functionsA function operation where one function is applied to the output of another function, written as (f ∘ g)(x) = f(g(x)).
contextual restrictionsLimitations on a function's domain or range based on the real-world context or practical applicability of the function.
domainThe set of all possible input values for which a function is defined.
identity functionThe function h(x) = x, which serves as the line of reflection between inverse exponential and logarithmic functions.
inputThe independent variable or value that is entered into a function.
input valueThe x-values or independent variable values used as inputs to a function.
inverse functionA function that reverses the mapping of another function, such that if f(x) = y, then f⁻¹(y) = x.
inverse operationsOperations that undo each other, such as addition and subtraction or exponentiation and logarithms, used to reverse a function's mapping.
invertible domainThe domain of a function on which the function is one-to-one and therefore has an inverse function.
invertible functionA function that has an inverse function; a one-to-one function where each output corresponds to exactly one input.
output valueThe y-values or results produced by a function for given input values.
reflection over the line y = xA transformation that reverses the roles of x- and y-coordinates, used to graph an inverse function.
reverse mappingThe process by which an inverse function exchanges the roles of inputs and outputs from the original function.

2.9 Logarithmic Expressions

TermDefinition
baseThe number b in exponential functions b^x or logarithmic functions log_b x, where b > 0 and b ≠ 1.
common logarithmA logarithm with base 10, used when the base of a logarithmic expression is not specified.
exponential formThe representation of a logarithmic equation in the form b^a = c, equivalent to the logarithmic form log_b c = a.
logarithmThe exponent or power to which a base must be raised to obtain a given number.
logarithmic expressionA mathematical expression of the form log_b c, where b is the base and c is the argument, representing the exponent to which the base must be raised to obtain the value c.
logarithmic scaleA scale where each unit represents a multiplicative change equal to the base of the logarithm, such as powers of 10 on a base-10 logarithmic scale.