Calculas
If limx→a− f(x)=L and limx→a+ f(x)=M, where L and M are finite real numbers, then what must be true about L and M in order for limx→a f(x) to exist?
L=M
Which of the following is the correct formula for average velocity?
vav= s(b)-s(a)/b-a
What is a vertical asymptote?
A vertical asymptote is a vertical line x=a, which the graph of a function approaches as x approaches a
When limx→a f(x) exists, it always equals f(a). State whether this statement is true or false.
False. The limit (if it exists) depends on values of f near a, but it does not depend on the value of f(a)
State the precise definition of lim z→c h(z)=P.
For any number ε>0, there is a corresponding number δ>0 such that h(z)−P<ε whenever 0<z−c<δ
We informally describe a function f to be continuous at a if its graph contains no holes or breaks at a. Explain why this is not an adequate definition of continuity.
A graph may not be precise enough to show points of discontinuity in a complicated function
Explain the meaning of limx→b− r(x)=K.
As x approaches b from the left, the value of r(x) approaches K
Explain the meaning of limx→−∞ f(x)=10
As x becomes arbitrarily large in magnitude and negative, the value of f(x) approaches 10
State whether each of the following functions are continuous or not for all values in their domain: T(t)= temperature t minutes after midnight in Chicago on January 1.
The function T(t) is continuous because the temperature changes gradually as time increases, with no jumps in between
State whether each of the following functions are continuous or not for all values in their domain: a(t)= altitude of a skydiver t seconds after jumping from a plane.
The function a(t) is continuous because the skydiver's altitude decreases as time increases, with no breaks in between
State whether each of the following functions are continuous or not for all values in their domain: n(t)= number of quarters needed to park in a metered parking space for t minutes.
The function n(t) is discontinuous because the number of quarters must be a whole number
State whether each of the following functions are continuous or not for all values in their domain: p(t)= number of points scored by a baseball player after t minutes of a baseball game.
The function p(t) is discontinuous because the number of points must be a whole number
Determine whether the following statements are true and give an explanation or counterexample: For a given ε>0, there is one value of δ>0 for which f(x)−L<ε whenever 0<x−a<δ.
The statement is false. For any δ>0, every δ0 with 0<δ0<δ also satisfies the condition that f(x)−L<ε because 0<x−a<δ holds whenever 0<x−a<δ0 holds
Determine whether the following statements are true and give an explanation or counterexample: The limit limx→a f(x)=L means that given an arbitrary δ>0, an ε>0 can always be found such that f(x)−L<ε whenever 0<x−a<δ.
The statement is false. It may not be possible to bound the function to within ε of L on an interval of x within δ of a for arbitrary δ, even if the limit exists
Determine whether the following statements are true and give an explanation or counterexample: The limit lim x→a f(x)=L means that given any arbitrary ε>0, a δ>0 can always be found such that f(x)−L<ε whenever 0<x−a<δ.
The statement is true. This is the precise definition of the limit
Determine whether the following statements are true and give an explanation or counterexample: If x−a<δ, then a−δ<x<a+δ.
The statement is true, because x−a<δ means −δ<x−a<δ by the definition of the absolute value, from which the above follows
For what values of a does limx→a r(x)=r(a) if r is a rational function?
Those values of a for which the denominator of the function r is not zero
Give the three conditions that must be satisfied by a function to be continuous at a point.
lim x→a f(x) exists, f(a) is defined, lim x→a f(x)=f(a)
How is limx→a p(x) calculated if p is a polynomial function?
lim x→a p(x)= p(a)
A function is continuous from the right at a if
lim x→a+ f(x)= f(a)
A function is continuous from the left at a if
lim x→a- f(x)= f(a)
How are limx→a− p(x) and limx→a+ p(x) calculated if p is a polynomial function?
lim x→a- p(x)= lim x→a+ p(x)= p(a)
Which of the following is the correct formula for the slope of the secant line?
msec= s(b)-s(a)/b-a
Which of the following is the correct formula for the slope of the tangent line?
mtan= lim t→a f(t)-f(a)/t-a