Jan 28 - Feb 1 Flashcards
Calculating Limits using Limit Laws 2.3 Continuity 2.5
Limits Laws
Suppose that c is that constant and the limits
lim f(x) x->a
and
lim g(x) x->a
- lim [f(x) + g(x)] = lim f(x) + lim g(x)
all while x approaches a
- lim [f(x) - g(x)] = lim f(x) - lim g(x)
- lim [cf(x)] = clim f(x)
- lim [f(x) g(x)] = lim f(x) * lim g(x)
- lim f(x)/g(x) = lim f(x)/ li g(x) if lim g(x) DOES NOT equal 0
Five Laws Verbally
- Sum Law: The limit of a sum is the sum of the limits.
- Difference Law: The limit of a difference is the difference of the limits.
- Constant Multiple Law: The limit of a constant times a function is the constant times the limit of the function.
- Product Law: The limit of a product is the product of the limits.
- Quotient Law: The limit of a quotient is the quotient of the limits.
Power Law
(all while x approaches a)
lim [f(x)]^ n = [lim f(x)]^ n
In applying these six limits laws, we need to use two special limits
lim c = c
lim x = a
Root Law
(x is approaching a)
lim ^n /f(x) = ^n/limf(x)
assume n is a positive integer
Direct Substitution Property
If f is a polynomial or a rational function and a is in the domain of f then
lim f(x) = f(a) x->a
Two-Sided Limit Exists If and Only IF Theorem
lim f(x) = L x->a
if and only if
lim f(x) = L = lim f(x) x->a x->a+
If f(x) /< g(x) when x is near a and the limits of f and g both exist as x approaches a, then
(x is approaching a)
lim f(x) /< lim g(x)
Squeeze Theorem
if f(x) /< g(x) /< h(x) when x is near a and
lim f(x) = lim h(x) = L
all while x is approaching a
a function f is a continuous at a number a if
(x is approaching a)
lim f(x) = f(a)