Page 902 - Algebra 1

Permutations and Combinations
Symbols
P(n, r)
C(n, r)
permutation of n things taken r at a time _
n! nPr = (n-r)!
combination of n things taken r at a
Comparison Symbols
time _
nCr = r!(n - r)!
< > ≤ ≥ ≠ ≈

°
∠ABC m∠ABC △ ABC A ⎯B
less than
greater than
less than or equal to greater than or equal to not equal to approximately equal to
is congruent to is similar to degree(s) angle ABC
the measure of angle ABC triangle ABC
line AB
segment AB
ray AB
length of AB
right angle
is perpendicular to is parallel to
n!
n!
Probability___ Geometry
n! = n · (n - 1) · (n - 2) · ... · 3 · 2 · 1
number of
P(event) = total number of outcomes
favorable P(A) probability of event A
Probability of complement
P(not event) = 1- P(event) Probability of independent events
P(A and B) = P(A) · P(B) Probability of dependent events
P(A then B) = P(A) · P(B after A) Probability of mutually exclusive events
P(A or B) = P(A) + P(B) Probability of inclusive events
P(A or B) = P(A) + P(B) - P(A and B) Additional Formulas
−−
outcomes
AB
⎯
AB AB
−−
⊥ ||
Direct variation Inverse variation Distance formula Distance traveled Exponential decay Exponential growth Midpoint of a segment
Real Numbers
y = kx
y = _k ; x ≠ 0
the set of real numbers
the set of rational numbers the set of integers
the set of whole numbers the set of natural numbers
x
d = √(x2 - x1)2 + (y2 - y1)2

d = rt
y = kbx; k > 0, 0 < b < 1
y = kbx; k > 0, b > 1
12 _
_ 22
M = (x + x , y1 + y2 )
Properties and Formulas 887
PROPERTIES AND FORMULAS