Indefinite Integrals or Antiderivatives You should distinguish carefully between definite and indefinite integrals. A definite integral is a number, whereas an indefinite integral is a function (or family of functions).
Antiderivative An antiderivative of a function f is a function F such that Ex.An antiderivative of since is
means to find the set of all antiderivatives of f. The expression: read “the indefinite integral of f with respect to x,” Integral sign Integrand Indefinite Integral x is called the variable of integration
Every antiderivative F of f must be of the form F(x) = G(x) + C, where C is a constant. Notice Constant of Integration Represents every possible antiderivative of 6x.
Power Rule for the Indefinite Integral, Part I Ex.
Power Rule for the Indefinite Integral, Part II Indefinite Integral of e x and b x
Sum and Difference Rules Ex. Constant Multiple Rule Ex.
The Definite Integral As a Total If r(x) is the rate of change of a quantity Q (in units of Q per unit of x), then the total or accumulated change of the quantity as x changes from a to b is given by
The Definite Integral As a Total Ex. If at time t minutes you are traveling at a rate of v(t) feet per minute, then the total distance traveled in feet from minute 2 to minute 10 is given by
Net or Total Change as the Integral of a Rate Integral of a rate of change Total change over
A honey bee makes several trips from the hive to a flower garden. The velocity graph is shown below. What is the total distance traveled by the bee? 200ft 100ft 700 feet
What is the displacement of the bee? 200ft -200ft 200ft -100ft 100 feet towards the hive
To find the displacement (position shift) from the velocity function, we just integrate the function. The negative areas below the x-axis subtract from the total displacement. To find distance traveled we have to use absolute value. Find the roots of the velocity equation and integrate in pieces, just like when we found the area between a curve and the x-axis. (Take the absolute value of each integral.) Or you can use your calculator to integrate the absolute value of the velocity function.
velocity graph position graph Displacement: Distance Traveled:
Examples A particle moves along a line so that its velocity at time t is (in meters per second): Find the displacement of the particle during the period Find the total distance travelled during the same period
Examples A factory produces bicycles at a rate of (in t weeks) How many bicycles were produced from day 8 to 21?
Examples At 7 AM, water begins leaking from a tank at a rate of (t is the number of hours after 7 AM) How much water is lost between 9 and 11 AM?
In the linear motion equation: V(t) is a function of time. For a very small change in time, V(t) can be considered a constant. We add up all the small changes in S to get the total distance.
As the number of subintervals becomes infinitely large (and the width becomes infinitely small), we have integration.
This same technique is used in many different real-life problems.
Example 5: National Potato Consumption The rate of potato consumption for a particular country was: where t is the number of years since 1970 and C is in millions of bushels per year. For a small, the rate of consumption is constant. The amount consumed during that short time is
Example 5: National Potato Consumption The amount consumed during that short time is We add up all these small amounts to get the total consumption: From the beginning of 1972 to the end of 1973: million bushels