Glossary
Accumulation of change
The total sum of how much a quantity has changed over a specified period of time, often represented by the area under a rate-of-change curve.
Example:
Calculating the total accumulation of change in a bank account balance after a year of deposits and withdrawals.
Anti-derivatives
The reverse process of differentiation; a function whose derivative is the original function.
Example:
If the derivative of is , then is an anti-derivative of . For instance, is an anti-derivative of .
Approximating (area under the curve)
The process of estimating the value of the area under a curve, often using methods like Riemann sums, when an exact calculation is difficult or unnecessary.
Example:
When you use a trapezoidal rule to estimate the distance traveled from a complex velocity graph, you are approximating the area under the curve.
Area under the curve
The region bounded by a function's graph, the x-axis, and vertical lines at specified intervals, representing the total accumulation of the quantity.
Example:
The area under the curve of a velocity-time graph gives the total distance traveled.
Definite integral
An integral evaluated over a specific interval, yielding a numerical value that represents the net accumulation or signed area under the curve between the given limits.
Example:
The definite integral would give the total displacement of an object from time to .
Independent variable
The variable in a function whose value is freely chosen or manipulated, and which determines the value of the dependent variable.
Example:
In the function , x is the independent variable that we can choose, and it affects the value of y.
Integral
A mathematical operation that calculates the total accumulation of a quantity, representing the exact area under a curve.
Example:
To find the total volume of water that has flowed into a tank given its flow rate function, you would compute the integral of the flow rate.
Rate of change
A measure of how one quantity changes in relation to another quantity, typically expressed as a derivative or a ratio.
Example:
The rate of change of a car's position is its velocity, measured in miles per hour.
Riemann Sum
A method for approximating the area under a curve by dividing the region into a series of simple shapes, typically rectangles, and summing their areas.
Example:
To estimate the total water flow into a reservoir over a day, you could use a Riemann Sum by measuring the flow rate every hour and multiplying by the time interval.
Signed (area)
Area that accounts for direction, where area above the x-axis is positive and area below the x-axis is negative, reflecting net change.
Example:
If a car drives forward for a while and then backward, the signed area under its velocity-time graph would represent its net displacement, not total distance.