Glossary
Approximation
A value or result that is close to the true value but not exact, often used when an exact calculation is difficult or impossible.
Example:
When using a finite difference method to estimate a derivative, you are finding an approximation of the true instantaneous rate of change.
Asymptote
A line that a graph approaches infinitely closely but never actually touches, indicating a point where the function is undefined or approaches infinity.
Example:
The function has a vertical asymptote at and a horizontal asymptote at .
Average Rate of Change
The measure of how a quantity changes over a specific interval, calculated as the ratio of the change in the dependent variable to the change in the independent variable.
Example:
If a runner covers 10 kilometers in 50 minutes, their Average Rate of Change of distance is 0.2 km per minute.
Average Rate of Change
The overall rate at which a function's value changes over an interval, calculated as the slope of the secant line connecting two points on the function's graph.
Example:
If a runner covers 10 km in 1 hour, their average rate of change (speed) is 10 km/h, even if they ran faster or slower at different times.
Continuous
A function is continuous if its graph can be drawn without lifting the pen, meaning there are no breaks, holes, or jumps.
Example:
A polynomial function like is continuous everywhere, as its graph is a smooth, unbroken curve.
Continuous
A function is continuous at a point if its graph can be drawn without lifting the pen, meaning the limit of the function at that point equals the function's value at that point.
Example:
A polynomial function like is continuous everywhere, having no breaks or jumps.
Coordinates
A set of values that specify the exact position of a point in a plane or space, typically represented as (x, y) for 2D graphs.
Example:
The point where a graph crosses the x-axis might have coordinates like (3, 0), indicating its position.
Cusp
A point on a curve where the direction of the curve changes abruptly, creating a sharp point, and the derivative does not exist.
Example:
The graph of has a sharp cusp at , which is why it's continuous but not differentiable there.
Derivative
The instantaneous rate of change of a function at a specific point, representing the slope of the tangent line to the function's graph at that point.
Example:
If a car's position is given by , its derivative gives the car's instantaneous velocity at time .
Derivative
The derivative of a function measures its instantaneous rate of change at any point, representing the slope of the curve at that specific point.
Example:
If , the derivative tells you the slope of the parabola at any x-value.
Derivative
A fundamental concept in calculus that measures the instantaneous rate at which a function's output changes with respect to its input, representing the slope of the tangent line.
Example:
The derivative of a position function with respect to time gives you the instantaneous velocity of an object.
Derivative
The derivative of a function measures the instantaneous rate at which the function's output changes with respect to its input. It is defined by a limit.
Example:
If a car's position is given by , its derivative gives its instantaneous velocity at any time t.
Differentiable
A function is differentiable at a point if its derivative exists at that point, implying the graph is smooth and has no sharp corners or vertical tangents.
Example:
The absolute value function is not differentiable at because its graph has a sharp corner there.
Differentiable
A function is differentiable at a point if its derivative exists at that point. A differentiable function has a derivative that exists at every point in its domain.
Example:
The function is differentiable everywhere, meaning you can find its slope at any point.
Domain
The set of all possible input values (x-values) for which a function is defined.
Example:
For , the domain is , as you cannot take the square root of a negative number in real numbers.
Equation of a Straight Line
The equation of a straight line is a linear relationship between x and y, commonly expressed as $y = mx + c$ (slope-intercept form) or $y - y_1 = m(x - x_1)$ (point-slope form).
Example:
The line is an equation of a straight line with a slope of 2 and a y-intercept of 1.
Equation of a Tangent Line
The equation of a tangent line is a linear equation ($y = mx + c$) that describes the straight line touching a curve at a specific point, with its slope determined by the derivative at that point.
Example:
Finding the equation of a tangent line to at involves calculating the derivative at to get the slope, then using the point-slope form.
Function
A function is a relation where each input has exactly one output; in calculus, the derivative itself can be a new function derived from the original.
Example:
If , its derivative is also a function that provides the slope for any given .
Function
A relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output.
Example:
The relationship between the radius of a circle and its area, A = πr², is a function where the area is dependent on the radius.
Function Notation
A standardized way to represent functions and their inputs/outputs, typically using symbols like $f(x)$ where $f$ is the function name and $x$ is the input variable.
Example:
If a function describes the temperature over time, uses Function Notation to represent the temperature at hour .
Horizontal Tangent
A horizontal tangent is a tangent line with a slope of zero, indicating a local maximum, minimum, or a saddle point on the curve.
Example:
The parabola has a horizontal tangent at its vertex , where its derivative is zero.
Instantaneous Rate of Change
The instantaneous rate of change is the rate at which a function's value changes at a specific, single point, rather than over an interval.
Example:
The speedometer in a car shows your instantaneous rate of change of distance with respect to time, not your average speed over a trip.
Instantaneous Rate of Change
The rate at which a function's value is changing at a single, specific point, representing the slope of the tangent line to the function's graph at that point.
Example:
When a car's speedometer reads 60 km/h, it's showing the instantaneous rate of change of its position at that exact moment.
Limit
A value that a function approaches as the input approaches some specific value, without necessarily reaching it. It's fundamental to calculus definitions.
Example:
As you get closer and closer to a wall, the limit of your distance to the wall is zero, even if you never actually touch it.
Limit
The value that a function approaches as its input approaches a certain value. It describes the behavior of a function near a point.
Example:
The limit of as approaches 0 is 1, even though the function is undefined at .
One-sided limits
The value a function approaches as the input approaches a point from either the left (values less than the point) or the right (values greater than the point).
Example:
For the absolute value function at , the one-sided limit from the left is -1, and from the right is 1.
Oscillates
Describes a function whose values fluctuate rapidly between different values as the input approaches a certain point, preventing the limit from settling on a single value.
Example:
The function oscillates infinitely many times between -1 and 1 as approaches 0, so its limit does not exist.
Slope
The measure of the steepness or incline of a line, calculated as the ratio of the vertical change (rise) to the horizontal change (run).
Example:
A road with a slope of 0.1 means that for every 10 meters horizontally, it rises 1 meter vertically.
Slope
A numerical value that describes the steepness and direction of a line, calculated as the ratio of the vertical change (rise) to the horizontal change (run) between two points.
Example:
When graphing the cost of a taxi ride versus distance, the Slope of the line represents the cost per mile.
Slope
Slope is a measure of the steepness and direction of a line, calculated as the ratio of the vertical change (rise) to the horizontal change (run).
Example:
A road sign indicating a 10% grade means the slope of the road is 0.1, rising 10 units for every 100 units horizontally.
Slope
A measure of the steepness and direction of a line, calculated as the ratio of the vertical change to the horizontal change between two points.
Example:
A ski slope with a slope of -0.5 means for every 10 meters horizontally, the elevation drops by 5 meters.
Slope of line segments
The measure of steepness between two distinct points on a graph, calculated as the change in y divided by the change in x.
Example:
When estimating the derivative of a function from a table, you might calculate the slope of line segments between adjacent data points to approximate the rate of change.
Slope of the Curve
The slope of the curve at a specific point is the steepness of the curve at that exact location, which is given by the derivative at that point.
Example:
For , the slope of the curve at is , indicating how steeply the graph rises there.
Slope of the tangent
The steepness of the line that touches a curve at a single point, indicating the instantaneous rate of change of the function at that point.
Example:
To find the instantaneous velocity of a ball thrown upwards at 2 seconds, you'd calculate the slope of the tangent to its height-vs-time graph at .
Specific point
A single, precisely defined location on a graph or within a function's domain, where a property like the instantaneous rate of change is evaluated.
Example:
To find the temperature change at exactly noon, you'd look at the specific point on the temperature-time graph corresponding to 12:00 PM.
Tangent
A tangent is a straight line that touches a curve at a single point, sharing the same slope as the curve at that specific point.
Example:
Imagine a ball rolling down a hill; if it suddenly flew off, its path would be a tangent to the hill's curve at the point it left.
Twice differentiable
A function is twice differentiable if its first derivative is also continuous and differentiable, meaning the second derivative exists.
Example:
If a function describes position, being twice differentiable means not only can you find its velocity (first derivative), but also its acceleration (second derivative).
Unbounded
Describes a function whose values grow infinitely large (positive or negative) as the input approaches a certain point, causing the limit not to exist.
Example:
The function is unbounded as approaches 0, as its values shoot up to infinity.
Vertical Asymptote
A vertical asymptote is a vertical line that a function's graph approaches infinitely closely but never touches or crosses, typically where the function itself is undefined.
Example:
The function has a vertical asymptote at , as the function's value approaches infinity as approaches 0.
Vertical Tangent
A vertical tangent is a tangent line with an undefined slope, occurring at points where the derivative approaches infinity or negative infinity.
Example:
The function has a vertical tangent at , where its derivative is undefined.
Vertical tangent
A point on a curve where the tangent line is vertical, meaning the slope is undefined and the derivative does not exist.
Example:
The function has a vertical tangent at , where its graph becomes momentarily vertical.