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- à 2.1èInductive Reasonïg
- äèPlease answer ê followïg questions about ïductive
- reasonïg.
- â
-
- èèèèèèPredict ê next number by ïductive reasonïg.
-
- èèèèèèèèèèèè 2, 4, 6, 8, 10, ______
- éS In ê first chapter we looked at three undefïed terms, twenty-
- six defïitions, å fourteen axioms.èSïce we are followïg Euclid's
- approach ë developïg geometry, ê next step is ë prove some add-
- tional geometric facts that we will call êorems.è
- è The process is ë accept ê undefïed terms, use ê defïitions as
- defïed facts, assume that ê axioms are facts, ên use all ç êse
- facts å Arisëtle's method ç deductive reasonïg ë prove new geo-
- metric facts.èSïce ê defïitions, axioms, å possibly already pro-
- ven êorems are ê facts that are used ë prove new facts, it is prac-
- tically essential ë commit all defïitions, axioms, å êorems ë
- memory.èTHIS IS THE KEY TO BEING SUCCESSFUL IN GEOMETRY.
- è Sïce this is difficult ë do, we have placed complete lists ç
- symbols, undefïed terms, defïitions, axioms, å êrems ï ê "help
- files" for easy reference.èThey are listed êre by section å chapter
- as êy occur ï this program.èPlease use êse "help files" as need-
- ed when tryïg ë justify a step ï a deductive proç by referrïg ë aè
- known fact.
- è To better understå ê nature ç deductive reasonïg, we will first
- look at ïductive reasonïg.èInductive reasonïg is used when we ob-
- serve a pattern occur several times, å based on êse observations
- predict what will happen next.èThis is a great ëol that we use
- all ê time ï everyday life å ï science å maêmatics.èIt helps
- us discover patterns that may be universal truths.
- è The down side ç ïductive reasonïg is that even though you observe
- a pattern occur a thouså times, it may not occur ê next time.èFor
- example, your alarm clock could wake you up every mornïg for years, å
- based on that pattern you set it expectïg ë wake up on time.èAs you
- have probably experienced on occasion, sometimes it doesn't work.èThus,
- when we use ïductive reasonïg we are just guessïg that somethïg will
- happen based on a few observations.
- è Deductive reasonïg comes ïë play after you have used ïductive
- reasonïg.èSome ç ê patterns that we discover usïg ïductive rea-
- sonïg actually are universal truths.èIn ê next section we will look
- at ê method ç deductive reasonïg ë prove some algebraic universal
- facts.
- è Thus, ïductive reasonïg is ê powerful ëol that we use all ê
- time ë observe patterns å predict ê next outcome.èHowever, ï ê
- event that ê pattern is actully always true, we can use deductive rea-
- sonïg ë prove that it will always occur å hence accept ê pattern
- as a new fact.
- è In this section, however, we are just goïg ë have fun å use our
- ïductive reasonïg ë predict ê next outcome based on ê patterns
- apparent from a few cases.èWe won't make ê same mistake that ê
- great astronomer, Bode, made when he observed ê distances ç planets
- from ê sun.
-
- èMercuryèè Venusèè Earthèè Marsèèèèèèè Jupiterèè Saturn
- èè.4èèèèè.7èèè 1.0èèè 1.6èèè 2.8èèè 5.2èèèè 10
-
-
- èUranusèè Neptuneèè Plaë
- è 19.6èèèèèèèèè38.8
-
- The planet Uranus was found ï ê predicted position strengênïg
- Bode's rule, but only asteroids were found at a distance ç 2.8 å
- Neptunes was discovered ï 1846 out ç ê predicted sequence.èOn one
- hå, ïductive reasonïg helped astronomers discover Uranus, a previ-
- ously unknown planet, however on ê oêr hå, ê sequence did not
- hold ï all cases.
- 1
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèèè 1, 3, 5, 7, 9, _____.
-
- èèèèè A) 10èèèèèB) 11èèèèèC) 13èèèèèD) None
- ü
-
- èèèèèèèèèè The numbers ïcrease by two.
-
- èèèèèèèèèèèèèèèè 11
- Ç B
- 2
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèèè 1, 4, 9, 16, 25, _____.
-
- èèèèè A) 49èèèèèB) 37èèèèèC) 36èèèèèD) None
- ü
-
- èèèèèèèèèThis is ê square number sequence.
-
- èèèèèèèèèèèèèèèèè36
- Ç C
- 3
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèè2, 3, 5, 7, 11, 13, 17, _____.
-
- èèèèè A) 19èèèèèB) 21èèèèèC) 23èèèèèD) None
- ü
-
- èèèèèèèèè This is ê prime number sequence.
-
- èèèèèèèèèèèèèèèèè 19
- Ç A
- 4
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèèèèè1, 8, 27, 64, _____.
-
- èèèèè A) 75èèèèèB) 125èèèèèC) 96èèèèèD) None
- ü
-
- èèèèèèèèèèThis is ê cube number sequence.
-
- èèèèèèèèèèèèèèèèè 125
- Ç B
- 5
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèèèè0, 2, 6, 12, 20, _____.
-
- èèèèè A) 30èèèèèB) 28èèèèèC) 32èèèèèD) None
- üèThere might be more than one way ë predict ê next term.èThe
- gap between ê numbers ïcreases by 2, ên 4, ên 6, ên 8.èThe
- next gap should be 10.èThat means ê next number should be 30.
- è Anoêr approach is ë use ê formula n² - n å substitute first 1,
- ên 2, ên 3, ên 4, ên 5, å fïally 6.èYou get 30 this way
- also.èèèèèèèèè
- Ç A
- 6
- èèèèèèUse ïductive reasonïg ë predict ê next number.
-
- èèèèèèèèèèè 1, 1, 2, 3, 5, 8, 13, _____.
-
- èèèèè A) 19èèèèèB) 17èèèèèC) 21èèèèèD) None
- üè
-
- èèèèèEach number is ê sum ç ê two preceedïg numbers.
- è
- èèèèèèèèèèèèèèè8 + 13 = 21
- èèèèèèèèè
- Ç C
- 7èSuppose you are observïg ê ïtensity ç a light from a
- èèèèè boat as it moves away from you.èPredict ê next number.
-
- èèèèè Distanceèè 10èèè20èèè30èèè40èèè50
- èèèèè Intensityèè 1èè 1/4èè 1/9èè 1/16èè __
-
- èèèèA) 1/36èèèèèB) 1/25èèèèèC) 1/27èèèèèD) None
- üè
-
- èèèè
- èèèèè Intensity = 100/(distance)² = 100/(50)² = 1/25èèèèèèèèèèèèèèèèèè
- Ç B
- 8èSuppose you are measurïg ê volume ç a gas as you ïcrease
- èèèèè ê temperature.èPredict ê next number.
-
- èèèèè Temperatureèè 10èèè11èèè12èèè13èè 14
- èèèèè Volumeèèèèè20èèè22èèè24èèè26èè __
-
- èèèèèA) 28èèèèèB) 30èèèèèC) 29èèèèèD) None
- üè
-
- èèèèèèèèèèèè Volume = 2·Temperature
- èèèè
- èèèèèèèèèèèèèèèè2·14 = 28èèèèèèèèèèèèèèè
- Ç A
- 9èSuppose you are measurïg ê time ç a pendulum swïg asè
- you ïcrease ê length ç ê strïg.èPredict ê next number.
-
- èèèèè Timeèèèèèèèè 1èèè2èèè3èèè4èèè5
- èèèèè Length ç strïgèè 1èèè4èèè9èè 16èè __
-
- èèèèèA) 22èèèèèB) 27èèèèèC) 25èèèèèD) None
- üè
- èèèè
- èèèèèThe length ç ê strïg equals ê square ç ê time.è
-
- èèèèèèèèèèèèèèèè 25èèèèèèèèèèèèèèèè
- Ç C
- 10èSuppose you are measurïg ê volume ç a gas as youè
- èèèèèèïcrease ê pressure.èPredict ê next number.
-
- èèèèè Pressureè 1èèè2èèè3èèè4èèè5èèè6èèè7
- èèèèè Volumeèè 2èèè1èè 2/3èè1/2èè2/5èè1/3èè__
-
- èèèèèA) 2/9èèèèèB) 1/5èèèèèC) 2/7èèèèèD) None
- üè
-
- èèèè
- èèèèèèèèèèè Volume = 2/Pressure = 2/7èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
- Ç C
- 11èSuppose you are observïg ê number ç CDs you can sellè
- èèèèèèas you ïcrease ê price.èPredict ê next number.
-
- èèèèèèèèè Priceèèèèèè1èèè2èèè3èèè4èè
- èèèèèèèèè Number Soldèè 24èè 12èèè8èèè__
-
- èèèèèèèA) 2èèèèèB) 6èèèèèC) 4èèèèèD) None
- üè
-
- èèèè
- èèèèèèèèèèNumber Sold = 24/Price = 24/4 = 6èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
- Ç B
- 12èSuppose you are fïdïg ê area ç a rectangle as youè
- èèèèèèchange ê dimensions.èPredict ê next number.
-
- èè Dimensionsèè 2 by 3èèè 3 by 4èèè 4 by 5èèè 5 by 6è
- èè Areaèèèèèèè6èèèèè 12èèèèè 20èèèèè __
-
- èèèè A) 30èèèèèB) 32èèèèèC) 40èèèè D) None
- üè
-
- èèèè
- èèèèèèèèè Area = Length x Width = 5 x 6 = 30èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
- Ç A
- 13èSuppose you are observïg ê distance an object falls ï aèè
- èèèèèègiven amount ç time.èPredict ê next number.
-
- èèèèèèèèèTimeèèè1èèèè2èèèè3èèèè4èèèèèè
- èèèèèèèèèDistanceè2èèèè8èèè 18èèè __
-
- èèèè A) 44èèèèèB) 32èèèèèC) 64èèèè D) None
- üè
-
- èèèè
- èèèèèèèèèèDistance = 2(Time)² = 2(4)² = 32èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
- Ç B
- 14èSuppose you are recordïg ê force required ë stretchèè
- èèèèèèa sprïg a given distance.èPredict ê next number.
-
- èèèèèèèè Forceèèè 1èèèè2èèèè3èèèè4èèèèèè
- èèèèèèèè Distanceèè3èèèè6èèèè9èèè __
-
- èèèè A) 15èèèèèB) 14èèèèèC) 12èèèè D) None
- üè
-
- èèèè
- èèèèèèèèèè Force = 3·Distance = 3·4 = 12èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
- Ç C
-
- èèèèèèèèèèèèèèèèè
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