Chapter 8 (Alg 2) Flashcards
Exponential function
y = ab^x where a DNE 0 and b>1
Exponential growth function
if a > 0, b > 1 for a Exponential Function, y grows as x increases {} Graph rises from left to right graph passes through o,a and 1,ab Domain is all real numbers range is y > 0
Asymptote
A line that a graph approaches more and more closely
The x-axis is an asymptote of the graph of y = ab^x
Exponential decay function
y = ab^x where a > 0 and 0 0
Exponential growth, Exponential decay
y = a(1 + r)^t
y = a(1 - r)^t
a is the initial amount, r is the percent increase or decrease written as a decimal, t is the number of time periods
Growth factor
The quantity of (1 + r)
Decay factor
The quantity of (1 - r)
Compound Interest
Initial principal P deposited in an account that pays interest at an annual rate r (expressed as a decimal), compounded n times per year on previously earned interest
Amount a in the account after t years can be modeled
A = P(1 + r/n)^nt
natural base e
Euler’s number
irrational, defined as followed,
as n approaches + inf. (1 + 1/n)^n
Common Logarithm
log with base 10 simply denoted by log
Logarithm of y with base b
denoted by log base b of y
Defined as log base b of y = x if and only if
b^x = y
Special Logarithm Values
Log of 1 {} log base 1 = 0
Logarithm of base b {} log base b = 1
Inverse Functions
g(f(x)) = log base b of b^x = x f(g(x)) = b^log base b of x = x
Graphing logarithmic Functions
the graph of y = log base b of x is the reflection of the graph of y = b^x in the line y = x
The graph of y = log base b of x includes (1,0) and (b,1)
The y-axis is a vertical asymptote
The domain is x > 0, and the range is all real numbers
To graph logs
y = log base b (x - h), translate the graph of y = log base b of x horizontally h units. y = log base b of x + h, translate the graph of y = log base b of x vertically k units