Chapter 2 Flashcards
Define a limit?
Suppose f(x) s defined when (x) is near the number (a). This means that f is defined on some open interval that contains (a), except possibly at (a) itself.
lim(x-a)f(x) = L
“The limit of f(x), as (x) approaches (a), equals L”
if we can make the values of f(x) arbitrarily close to L (as close as we like) by taking x to be sufficiently close to (a) (on either side of a) but not equal to (a)
Define one-sided limits?
lim(x-a^-)f(x) = L
and say that the LEFT-HANDED LIMIT OF F(X) AS (X) APPROACHES (A) (or as (x) approaches (a) from the left) is equal to L
if we can make the values of f(x) arbitrarily close to L by taking (x) to be sufficiently close to (a) and (x) less than (a)
same goes for a right handed-limit
Define Infinite Limits?
Let f be a function defined on both sides of (a), except possibly at (a) itself. Then…
lim(x-a)f(x) = ∞
means that the values of f(x) can be made arbitrarily large (as large as we please) by taking (x) sufficiently close to (a), but not equal to (a)
Let f be defined on both sides of (a), except possibly at (a) itself. Then…
lim(x-a)f(x) = -∞
means that the values of f(x) can be made arbitrarily large negative by taking (x) sufficiently close to (a), but not equal to (a)
what is a vertical asymptote?
the line x=a is called a vertical asymptote of the curve y=f(x) if at least one of the following statements is true
lim(x-a)f(x) = ∞ lim(x-a^-)f(x) = ∞ lim(x-a^+) = ∞ lim(x-a)f(x) = -∞ lim(x-a^-)f(x) = -∞ lim(x-a^+) = -∞
what are the limit laws?
- The limit of a sum is the sum of the limits lim(x-a)[f(x) + g(x)] = lim(x-a)f(x) + lim(x-a)g(x)
- The limit of a difference is the difference of the limits
lim(x-a)[f(x) - g(x)] = lim(x-a)f(x) - lim(x-a)g(x) - The limit of a constant times a function is the constant times the limit of the function
lim(x-a)[Cf(x)] = Clim(x-a)f(x) - The limit of a product is the product of the limits
lim(x-a)[f(x)g(x)] = lim(x-a)f(x)lim(x-a)g(x) - The limit of a quotient is the quotient of the limits (provided that the limit of the
denominator is not 0)
lim(x-a)[f(x) / g(x)] = lim(x-a)f(x) / lim(x-a)g(x); g(x) cannot equal 0
what is the direct substitution property?
If f is a polynomial or a rational and (a) is in the domain of f, then
Lim(x-a)f(x) = f(a)
what is the theorem that applies to limits?
If f(x)
what is the squeeze theorem?
It says that if g(x) is squeezed between f(x) and h(x) near (a), and if f and h have the same limit at (a), then g is forced to have the same limit L at (a)
If f(x) = g(x) = h(x) when (x) is near (a) (except possibly at (a)) and…
Lim(x-a)f(x) = Lim(x-a)h(x) = L then…
Lim(x-a)g(h) = L
A number divided by 0 = ?
Undefined
Zero divided by a number = ?
0
The special cubic factors for addition are?
a3 + b3 = (a + b)(a2 – ab + b2)
The special cubic factors for subtraction are?
a3 – b3 = (a – b)(a2 + ab + b2)
Define continuity?
A function f is continuous at a number (a) if..
Lim(x-a)f(x) = f(a)
A continuous process is one that takes place gradually, without interruption or abrupt change
what are the 4 things that determine if a function is continuous or not on a specific interval?
- f(a) is defined (that is, (a) is in the domain of f)
- Lim(x-a)f(x) exists
3.Lim(x-a)f(x) = f(a) - Lim(x-a^+)f(x) = f(a) = Lim(x-a^-)f(x) = f(a)
a function f is continuous at a number (a) and f is continuous from the left (a)
Define discontinuity?
If f is defined near (a) (in other words, f is defined on an open interval containing (a), except perhaps at (a)), we say f is discontinuous at (a), if f is not continuous at (a)
what is the Intermediate Value Theorem?
Suppose that f is continuous on a closed interval [a,b] and let N be any number between f(a) and f(b), where f(a) cannot equal f(b). Then there exists a number (c) in (a,b) such that f(c) = N
Intermediate Value Theorem states that a continuous function takes on every intermediate value between the function values f(a) and f(b)
What are limits to infinity: horizontal asymptotes?
Let f be a function defined on some interval (a, ∞). Then…
Lim(x-∞)f(x) = L
means that the values of f(x) can be made arbitrarily close to L by taking x-sufficiently large
What are limits to infinity: horizontal asymptotes negative?
Let f be a function defined on some interval (-∞, a). Then..
Lim(x->-∞)f(x) = L
means that the values of f(x) can be made arbitrarily close to L by taking x-sufficiently large NEGATIVE
what is a horizontal asymptote?
The line y=L is called a horizontal asymptote of the curve y=f(x) if either…
Lim(x->∞)f(x) = L or Lim(x->-∞)f(x) = L
To find the horizontal asymptote of a rational function without a square root, you do what?
divide the numerator and the denominator by the highest power of x in the denominator
To find the horizontal asymptote of a rational function that has a square root in the numerator, you do what?
divide the numbers under the square root, by the highest power of x underneath the square root. All the other numbers divide by the highest power of x in the entire function
what is a tangent line?
The slope of a curve at a point. The tangent line to the curve y = f(x) at a point P(a, f(a)) is the line through P with slope
m = lim(x-a) f(x) - f(a) / x -a
provided the limits
what is the instantaneous velocity?
v(a) at a time t=a to be the limit of these average velocities
v(a) = lim(h-0) f(a + h) - f(a) / h
what are the two derivative definitions?
- The derivative of a function f at a number (a), denoted by f’(a) is…..
f’(a) = Lim(h->0) f(a + h) - f(a) / h
- f’(a) = Lim(x->a) f(x) - f(a) / x - a
what are differentiation factors?
f’(x) = y’ = dy/dx = df/dx = d/dxf(x) = Df(x) = Dx f(x)
what determines if a function is differentiable?
a function is differentiable at (a) if f’(a) exists. It is differentiable on an open interval (a,b) or (a,∞) or (a, -∞)
If it is differentiable at every number in the interval
what determines if a function is non-differentiable?
- If a a graph of a function has a “kink” or a “corner” in it the graph has no tangent at this point and f is not differentiable there
- If the left and right limits are different, if f is not continuous at a, then f is not differentiable at a. So at any discontinuity (for instance, a jump discontinuity) f fails to be differentiable
- A third possibility is that the curve has a vertical tangent line when x a
what are higher derivatives? what is a seconds derivative of a function?
This new function f’’ is called the second derivative of f because it is the derivative of the derivative of f