Glossary
Accumulation of Change
The total amount of change in a quantity over an interval, determined by integrating its rate of change.
Example:
If a function describes the rate at which a population grows, the accumulation of change over a decade would tell you the total increase in population during that time.
Area Under the Curve
The region bounded by the graph of a function, the x-axis, and two vertical lines at the interval's endpoints, whose signed value is given by the definite integral.
Example:
If a graph shows the rate of water flowing into a pool, the area under the curve over a certain time period represents the total volume of water added.
Average Value of a Function
The average y-value of a continuous function over a given interval, calculated by integrating the function over that interval and dividing by the length of the interval.
Example:
To find the average value of a function representing the temperature of a metal rod over its length, you would integrate the temperature function along the rod and divide by the rod's length.
Continuous Function
A function whose graph can be drawn without lifting the pen, meaning there are no breaks, jumps, or holes in its domain.
Example:
The function is a continuous function for all real numbers, allowing us to apply the Average Value Theorem.
Definite Integral
An integral with upper and lower limits, representing the net accumulated change or the signed area under the curve of a function over a specific interval.
Example:
Calculating the definite integral of a car's acceleration function from to seconds gives the total change in its velocity during that time.
Interval
A set of real numbers between two specified endpoints, often denoted as $[a,b]$ for a closed interval.
Example:
When analyzing the average velocity of a particle, we might consider its motion over the interval from seconds to seconds.
Limits of Integration
The upper and lower bounds (a and b) of a definite integral, which define the specific interval over which the function is integrated.
Example:
In the integral , the values 0 and are the limits of integration.