Logarithms Flashcards
1
Q
What is the Product log rule?
log_b(x . y) = ?
A
log_b(x . y) = log_b(x) + log_b(y)
2
Q
What is the Quotient log rule?
log_b(x/y) =
A
log_b(x/y) = log_b(x) - log_b(y)
3
Q
What is the Power log rule?
A
log_b(x^n) = n . log_b(x)
4
Q
What is the change of base formula log rule? For changing the base of a logarithm from B to C
A
log_b(x) = log_c(x) / log_c(b)
5
Q
If no base for a log is given, what can we assume the base is?
A
10
6
Q
What is a common base for logs in econ/finance?
A
𝑒
7
Q
What is the exponential function?
A
𝑒^y
8
Q
How do we turn a negative logarithm into a positive one?
I.E -log_10(1/25)
A
We remove the minus sign and raise the exponent to the power of the negative value before the log:
-log_10(1/25) = log_10(1/25)^-1
