内容正文:
4.5 函数的应用(二)
4.5.3函数模型的应用(二)
池州一中 祖向阳
复习回顾
在分界点的右侧
例题分析
例5.假设你有一笔资金用于投资,现有三种投资方案供你选择,这三种方
案的回报如下:
方案一:每天回报40元;
长期投资应
选择方案三
方案二:第一天回报10元,以后每天比前一天多回报10元;
方案三:第一天回报0.4元,以后每天的回报比前一天翻一番.
请问,你会选择哪种投资方案?
定量计算
方案一
方案二
方案三
x
y=40
y=10x
y=0.4*2x-1
1
2
短期投资应
选择方案一
或者方案二
3
4
5
6
7
8
9
10
...
长期投资应
选择方案三
e4r0ies1,ꢀ11S, e4r0ies1,ꢀ12,ꢀ40
定性分析
每天的回报金额图
长期投资应
选择方案三
指
140
120
100
80
60
40
20
0
Series2,ꢀ12,ꢀ120
Series2,ꢀ11,ꢀ110
Series3,ꢀ9,ꢀ102.4
Series2,ꢀ10,ꢀ100
Series2,ꢀ9,ꢀ90
Series2,ꢀ8,ꢀ80
Series2,ꢀ7,ꢀ70
Series2,ꢀ6,ꢀ60
Series2,ꢀ5,ꢀ50
Series1,ꢀ1,ꢀS4e0ries1,ꢀ2,ꢀS4e0ries1,ꢀ3,ꢀS4e0ries21,ꢀ4,ꢀS4e0ries1,ꢀ5,ꢀS4e0ries1,ꢀ6,ꢀS4e0ries1,ꢀ7,ꢀS4e0ries1,ꢀ8,ꢀS4e0ries1,ꢀ9,ꢀS4e0ries1,ꢀ10S,
合理吗
?
Series3,ꢀ8,ꢀ51.2
Series2,ꢀ3,ꢀ30
Series2,ꢀ2,ꢀ20
Series2,ꢀ1,ꢀ10
短期投资:以累计
的回报金额为依据
Series3,ꢀ7,ꢀ25.6
Series3,ꢀ6,ꢀ12.8
Series3,ꢀ5,ꢀ6.4
Series3,ꢀ4,ꢀ3.2
Series3,ꢀ3,ꢀ1.6
Series3,ꢀ1,ꢀS0e.4ries3,ꢀ2,ꢀ0.8
0
2
4
6
8
10
12
14
定量计算
方案一
方案二
方案三
x
投资7天以内
应选择方案一
y=40
y=10x
y=0.4*2x-1
1
2
3
投资7天,应
选方案一或二
;投资8~10天
应选择方案二
4
5
6
7
8
9
投资10天以上
应选择方案三
10
11
定性分析
累计的回报金额图
900
Series3,ꢀ11,ꢀ818.8
Series2,ꢀ11,ꢀ650
800
700
600
500
400
300
200
100
0
Series2,ꢀ10,ꢀ550
Series2,ꢀ9,ꢀ450
Series1,ꢀ11,ꢀ440
Series3,ꢀ10,ꢀ409.2
Series1,ꢀ10,ꢀ400
Series2,ꢀ8,ꢀ36S0eries1,ꢀ9,ꢀ360
Series1,ꢀ8,ꢀ320
Series12,ꢀ7,ꢀ280
Series1,ꢀ6,ꢀ240
Series2,ꢀ6,ꢀ210
Series3,ꢀ9,ꢀ204.4
Series1,ꢀ5,ꢀ200
Series1,ꢀ4,ꢀ160
Series2,ꢀ5,ꢀ150
Series2,ꢀ4,ꢀ100
Series2,ꢀ3,ꢀ60
Series1,ꢀ3,ꢀ120
Series1,ꢀ2,ꢀ80
Series1,ꢀ1,ꢀ40
Series3,ꢀ1,ꢀ0.S4eries3,ꢀ2,ꢀ1.S2eries3,ꢀ3,ꢀ2.8
Series3,ꢀ8,ꢀ102
Series3,ꢀ7,ꢀ50.8
Series3,ꢀ6,ꢀ25.2
Series2,ꢀ2,ꢀ30
Series2,ꢀ1,ꢀ10
Series3,ꢀ4,ꢀ6
Series3,ꢀ5,ꢀ12.4
0
2
4
6
8
10
12
Series312,ꢀS1e,
r041i e.04s 32 , ꢀ SS2 ee,
定性分析
累计的回报金额图
指数爆炸
16000
14000
12000
10000
8000
6000
4000
2000
0
Series3,ꢀ16,ꢀ13516.4
Series3,ꢀ15,ꢀ6962.8
Series3,ꢀ14,ꢀ3686
Series3,ꢀ13,ꢀ2047.6
Series2,ꢀ16,ꢀ1360
Series2,ꢀ15,ꢀ1200
Series2,ꢀ14,ꢀ1050
Series2,ꢀ13,ꢀ910
Series3,ꢀ12,ꢀ1228.4
Series3,ꢀS1e1r,ꢀ8es128,.ꢀ812,ꢀ780
Series2,ꢀ11,ꢀ660
Series2,ꢀ10,ꢀ550
Series1,ꢀS1e4r, 00
i e5 Ss61e0,rꢀi1e5s 1, ,ꢀ16,ꢀ640
Series2,ꢀS9e,ꢀr4ie5s03,ꢀ10,ꢀ409.2Series1,ꢀS1e2r,
ie4s810,ꢀ13, 520
1 Ser es10,ꢀ11,
440
Series2,ꢀ7,ꢀ2801 S rie2s1,ꢀ9, 360
Series2,ꢀ8,ꢀ360
Series12,ꢀ6,ꢀ24101
Series3,ꢀ9,ꢀ204.4
Series1,ꢀS2e,
r8i0es1,ꢀS3e,
rr13ii ee.02ss 32 ,, ꢀꢀ S33 e,, r26i .0e8s 3 , ꢀS4e,
r1i e2s012 , ꢀS4e,
ꢀ
r6ies3,ꢀS5e, r1i e2s. 43 , ꢀS6e,
r1ie60s012,ꢀ5, 2105 0
ꢀ
r2ie5s.23,ꢀ7,ꢀ50.8
Series3,ꢀ8,ꢀ102
0
2
4
6
8
10
12
14
16
18
例题分析
SSeSereri rieei ses2s22, , 0101. 04 2
,
1,, 01.,
6
5
4
3
2
1
数形结合
SeSreierise3s,ꢀ ,ꢀ
SSeer ri ei ess32, ꢀ ꢀ
880055, ꢀ, ꢀ 5. 9 9
SeSreierise3s,ꢀ ,ꢀ S eSrei reise2s ,3
880066, ,ꢀ5.0028078,ꢀ057.0,ꢀ253
,ꢀ
880044, ,ꢀ5.983
选择奖励问题图
8
7
6
5
4
3
2
1
0
Series1,ꢀ30,ꢀ7.5
0
803.5
805.5
807.5
Series2,ꢀ900,ꢀ6.039
Series1,ꢀ20,ꢀ5
Series2,ꢀ800,ꢀ4.94
Series3,ꢀ900,ꢀ4.496
Series3,ꢀ800,ꢀ4.435
Series3,ꢀ600,ꢀ4.287
Series2,ꢀ600,ꢀ3.316
Series3,ꢀ400,ꢀ4.079
Series2,ꢀ400,ꢀ2.224
Series3,ꢀ200,ꢀ3.723
Series3,ꢀ150,ꢀ3.575
Series3,ꢀ100,ꢀ3.367
Series3,ꢀ55,ꢀ3.059
Series3,ꢀ30,ꢀ2.748
Series3,ꢀ20,ꢀ2.54
Series1,ꢀ10,ꢀ2.5
Series3,ꢀ10,ꢀ2.183
Series3,ꢀ5,ꢀ1.827
Series2,ꢀ200,ꢀ1.491
Series2,ꢀ150,ꢀ1.349
Series3,ꢀ2,ꢀ1.356
Series1,ꢀ5,ꢀ1.25Series2,ꢀ100,ꢀ1.221
Series2,ꢀ55,ꢀ1.116
S eSrei er ise2s,22, ꢀ03,01, ꢀ.10.4016 2
Series1,ꢀ2,ꢀ0.5
0
200
400
600
800
1000
回顾例题
怎样处理这个
限制条件呢?
SSeSereri rieei ses2s22, , 0101. 04 2
,
1,, 01.,
3
2.5
2
Series1,ꢀ11,ꢀ
2.75
数形结合
Series1,ꢀ10,ꢀ
2.5
Series1S,ꢀe9r,ꢀies2,ꢀ11,ꢀ
Series2,ꢀ10,ꢀ
Series2,ꢀ9,ꢀ
Series22,ꢀ.82,ꢀ
2.232
2.183
182, ꢀ92
SerieSse2ri,e
6se, 2
i, ꢀ 7s,2ꢀ 2,.
2.069
Series2,ꢀ5,ꢀ
1.827
1.S9e2r1ies1,ꢀ7,ꢀ
Series2,ꢀ4,ꢀ
Series2,ꢀ3,ꢀ
1.712
1.75
Series1,ꢀ6,ꢀ
1.5
1.5
1
1.565
Series2,ꢀ2,ꢀ
Series1,ꢀ5,ꢀ
1.301
1.25
选择奖励问题图
Series2,ꢀ1,ꢀ1Series1,ꢀ4,ꢀ1
Series1,ꢀ3,ꢀ
8
7
6
5
4
3
2
1
0
Series2,ꢀ0.5,ꢀ
0.75
Series1,ꢀ2,ꢀ
0.644
0.5
0
0.5
Series1,ꢀ30,ꢀ7.5
Series1,ꢀ1,ꢀ
Series1,ꢀ0.5,ꢀ
0.25
0.125
0
5
10
15
Series2,ꢀ900,ꢀ6.039
Series1,ꢀ20,ꢀ5
Series2,ꢀ800,ꢀ4.94
Series3,ꢀ900,ꢀ4.496
Series3,ꢀ800,ꢀ4.435
Series3,ꢀ600,ꢀ4.287
Series2,ꢀ600,ꢀ3.316
Series3,ꢀ400,ꢀ4.079
Series2,ꢀ400,ꢀ2.224
Series3,ꢀ200,ꢀ3.723
Series3,ꢀ150,ꢀ3.575
Series3,ꢀ100,ꢀ3.367
Series3,ꢀ55,ꢀ3.059
Series3,ꢀ30,ꢀ2.748
Series3,ꢀ20,ꢀ2.54
Series1,ꢀ10,ꢀ2.5
Series3,ꢀ10,ꢀ2.183
Series3,ꢀ5,ꢀ1.827
Series2,ꢀ200,ꢀ1.491
Series2,ꢀ150,ꢀ1.349
Series3,ꢀ2,ꢀ1.356
Series1,ꢀ5,ꢀ1.25Series2,ꢀ100,ꢀ1.221
Series2,ꢀ55,ꢀ1.116
S eSrei er ise2s,22, ꢀ03,01, ꢀ.10.4016 2
Series1,ꢀ2,ꢀ0.5
0
200
400
600
800
1000
Series2,ꢀ900,ꢀ6.039
SSeSereri rieei ses2s22, , 0101. 04 2
,
1,, 01.,
0
-50
SeSreierise1s,1,ꢀ50,ꢀ
10,
Series1,ꢀ
0
- 0 .-391. 479500
1000
1500
数形结合
100,ꢀ-21.633
Series1,ꢀ
200,ꢀ-46.277
Series1,ꢀ
400,ꢀ-95.921
-100
-150
-200
-250
-300
Series1,ꢀ
600,ꢀ-
145.713
选择奖励问题图
Series1,ꢀ
800,ꢀ-
195.565
8
7
6
5
4
3
2
1
0
Series1,ꢀ
1000,ꢀ-
245.45
Series1,ꢀ30,ꢀ7.5
Series1,ꢀ20,ꢀ5
Series2,ꢀ800,ꢀ4.94
Series3,ꢀ900,ꢀ4.496
Series3,ꢀ800,ꢀ4.435
Series3,ꢀ600,ꢀ4.287
Series2,ꢀ600,ꢀ3.316
Series3,ꢀ400,ꢀ4.079
Series2,ꢀ400,ꢀ2.224
Series3,ꢀ200,ꢀ3.723
Series3,ꢀ150,ꢀ3.575
Series3,ꢀ100,ꢀ3.367
Series3,ꢀ55,ꢀ3.059
Series3,ꢀ30,ꢀ2.748
Series3,ꢀ20,ꢀ2.54
Series1,ꢀ10,ꢀ2.5
Series3,ꢀ10,ꢀ2.183
Series3,ꢀ5,ꢀ1.827
Series2,ꢀ200,ꢀ1.491
Series2,ꢀ150,ꢀ1.349
Series3,ꢀ2,ꢀ1.356
Series1,ꢀ5,ꢀ1.25Series2,ꢀ100,ꢀ1.221
Series2,ꢀ55,ꢀ1.116
S eSrei er ise2s,22, ꢀ03,01, ꢀ.10.4016 2
Series1,ꢀ2,ꢀ0.5
0
200
400
600
800
1000
方案反思
8
7
6
5
4
3
2
1
0
分段限制奖
金的上限
Series1,ꢀ30,ꢀ7.5
Series1,ꢀ20,ꢀ5
Series2,ꢀ900,ꢀ4.496
Series2,ꢀ800,ꢀ4.435
Series2,ꢀ600,ꢀ4.287
Series2,ꢀ400,ꢀ4.079
Series2,ꢀ200,ꢀ3.723
Series2,ꢀ150,ꢀ3.575
Series2,ꢀ100,ꢀ3.367
Series2,ꢀ55,ꢀ3.059
Series2,ꢀ30,ꢀ2.748
Series2,ꢀ20,ꢀ2.54
Series1,ꢀ10,ꢀ2.5
Series2,ꢀ10,ꢀ2.183
Series2,ꢀ5,ꢀ1.827
Series2,ꢀ2,ꢀ1.356
Series1,ꢀ5,ꢀ1.25
Series1,ꢀ2,ꢀ0.5
0
200
400
600
800
1000
抽象概括
通过例5和例6 的分析,试概括选用函数类型构建数学模型解决实际
问题的一般步骤:
数学问题
转化
实际问题
函数模型
数
形
结
合
运 推
算 理
解释说明
实际问题的解
函数模型的解
课后作业:课本P.154第1,2
题
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