Chapter1
,1.1.1
AbsoluteValue
bsolutevalueisthenumericalvalueofanumberwithoutitssign. Thesymbolfor
A
absolutevalueistwoverticalbars,| |. Absolutevaluecanrepresentthedistanceona
numberlinebetweenanumberand0.Sinceadistanceisalwayspositive,theabsolute
valueisalwayseitherapositivevalueor0.Theabsolutevalueofanumberisnever
negative.
orexample,thenumber-3is3unitsawayfrom0,asshownonthenumberlineatright.
F
Therefore,theabsolutevalueof–3is3. Thisiswritten|− 3| = 3.
ikewise,thenumber5is5unitsawayfrom0. Theabsolutevalueof5is5,written
L
|5| = 5.
,1.1.2
FamiliesofFunctions
Functionscanbecategorizedinto“families”.
nefamilyoffunctionsisthelinearfunctions. Linearfunctionshaveagraphthatisa
O
straightline. Thelinemayormaynotpassthroughtheorigin,anditmaybeincreasing
ordecreasingfromlefttoright.
notherfunctionfamilyiscalleddirectvariation(also
A
calleddirectproportionorproportional),whichisalinear
functionthatpassesthroughtheorigin. It,too,maybe
increasingordecreasingfromlefttoright. Thedatayou
gatheredinthe“SignontheDottedLine”lab(inproblem
1-11)isanexampleofanincreasingproportion. Ina
proportionalsituation,ifthex-valueisdoubled(ortripled),
they-valueisalsodoubled(ortripled).
nexampleofadecreasingproportionistheelevationofa
A
submarineasitisdescending.
notherfunctionisinversevariation(alsocalledinverse
A
proportion). Thedatacollectedinthe“HotTubDesign”lab
(inproblem1-11)isanexampleofinversevariation.
oualsoobservedanexponentialfunction. Thegrowthof
Y
infectedpeopleinthe“FluEpidemic”(inproblem1-11)was
exponential.
ewilldefinewhatafunctionislaterinthischapter. Wewill
W
developlinearfunctionsandexponentialfunctionsinmuch
moredepthlaterinthiscourse.
, 1.1.3
TypesofAngles
hentryingtodescribeshapes,itisconvenientto
W
classifytypesofangles. Anangleisformedbytworays
joinedatacommonendpoint,calledavertex. The
measureofananglerepresentsthenumberofdegreesof
rotationfromoneraytotheotheraboutthevertex. This
coursewillusethefollowingtermstorefertoangles:
cuteAngle:Anyanglewithmeasurebetween(butnot
A
including)0ºand90º.
RightAngle:Anyanglethatmeasures90º.
btuseAngle:Anyanglewithmeasurebetween (butnot
O
including)90ºand180º.
traightAngle:Straightangleshaveameasureof180ºandare
S
formedwhenthesidesoftheangleformastraightline.
CircularAngle:Anyanglethatmeasures360º.
,1.1.1
AbsoluteValue
bsolutevalueisthenumericalvalueofanumberwithoutitssign. Thesymbolfor
A
absolutevalueistwoverticalbars,| |. Absolutevaluecanrepresentthedistanceona
numberlinebetweenanumberand0.Sinceadistanceisalwayspositive,theabsolute
valueisalwayseitherapositivevalueor0.Theabsolutevalueofanumberisnever
negative.
orexample,thenumber-3is3unitsawayfrom0,asshownonthenumberlineatright.
F
Therefore,theabsolutevalueof–3is3. Thisiswritten|− 3| = 3.
ikewise,thenumber5is5unitsawayfrom0. Theabsolutevalueof5is5,written
L
|5| = 5.
,1.1.2
FamiliesofFunctions
Functionscanbecategorizedinto“families”.
nefamilyoffunctionsisthelinearfunctions. Linearfunctionshaveagraphthatisa
O
straightline. Thelinemayormaynotpassthroughtheorigin,anditmaybeincreasing
ordecreasingfromlefttoright.
notherfunctionfamilyiscalleddirectvariation(also
A
calleddirectproportionorproportional),whichisalinear
functionthatpassesthroughtheorigin. It,too,maybe
increasingordecreasingfromlefttoright. Thedatayou
gatheredinthe“SignontheDottedLine”lab(inproblem
1-11)isanexampleofanincreasingproportion. Ina
proportionalsituation,ifthex-valueisdoubled(ortripled),
they-valueisalsodoubled(ortripled).
nexampleofadecreasingproportionistheelevationofa
A
submarineasitisdescending.
notherfunctionisinversevariation(alsocalledinverse
A
proportion). Thedatacollectedinthe“HotTubDesign”lab
(inproblem1-11)isanexampleofinversevariation.
oualsoobservedanexponentialfunction. Thegrowthof
Y
infectedpeopleinthe“FluEpidemic”(inproblem1-11)was
exponential.
ewilldefinewhatafunctionislaterinthischapter. Wewill
W
developlinearfunctionsandexponentialfunctionsinmuch
moredepthlaterinthiscourse.
, 1.1.3
TypesofAngles
hentryingtodescribeshapes,itisconvenientto
W
classifytypesofangles. Anangleisformedbytworays
joinedatacommonendpoint,calledavertex. The
measureofananglerepresentsthenumberofdegreesof
rotationfromoneraytotheotheraboutthevertex. This
coursewillusethefollowingtermstorefertoangles:
cuteAngle:Anyanglewithmeasurebetween(butnot
A
including)0ºand90º.
RightAngle:Anyanglethatmeasures90º.
btuseAngle:Anyanglewithmeasurebetween (butnot
O
including)90ºand180º.
traightAngle:Straightangleshaveameasureof180ºandare
S
formedwhenthesidesoftheangleformastraightline.
CircularAngle:Anyanglethatmeasures360º.