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2. 10.1(a) Types of functions (Chiang, p.26). 3. 4. 7.3.2 Inverse-function rule. This property of one to one mapping is unique to the class of functions known as monotonic functions:Definition of a function (p. 17)Function one y for each x andMonotonic function one x for each yOne x for each y, akainverse function.
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1. 1 Chiang Ch. 10 Exponential and Logarithmic Functions 10.1 The Nature of Exponential Functions
10.2 Natural Exponential Functions and the Problem of Growth
10.3 Logarithms
10.4 Logarithmic Functions
10.5 Derivatives of Exponential and Logarithmic Functions
10.6 Optimal Timing
10.7 Further Applications of Exponential and Logarithmic Derivatives
2. 2
3. 3
4. 4 7.3.2 Inverse-function rule This property of one to one mapping is unique to the class of functions known as monotonic functions:
Definition of a function (p. 17)
Function one y for each x and
Monotonic function one x for each y
One x for each y, aka inverse function
5. 5 7.3 Rules of Differentiation Involving Functions of Different Variables
6. 6
7. 7 10.1 The Nature of Exponential Functions 10.1(a) Simple exponential function
10.1(b) Graphical form
10.1(c) Generalized exponential function
10.1(d) A preferred base
8. 8 10.1(a) Simple exponential function
9. 9 10.1(c) Generalized exponential function Where
y = dependent variable
b = base
t = independent variable
a = vertical scale factor (directly related)
c = horizontal scale factor (inversely related)
10. 10 10.1(b) Graphical Exponential Functions y=bt where b=3,e,2
11. 11 10.1(d) A preferred base (e)
12. y1=e and y2=(1+1/m)m as m?? 12
13. 10.5 Derivative of the inverse of y=et, i.e. y=ln t (p. 277) 13
14. 10.5 Derivative of y=et using the Inverse function rule 14
15. 15 10.5(d) The case of base b
16. 16 10.1(d) A preferred base (e) (e) = 2.71828, irrational number w/ beautifully simple characteristics
17. 17 10.1(d) A preferred base (e) (e) = 2.71828, irrational number w/ beautifully simple characteristics)
18. 18 10.1(b) Graphic for f(x)=ex
19. 19 10.1(d) A preferred base (e) (e) = 2.71828, irrational number w/ beautifully simple characteristics)
20. 20 10.1(d) A preferred base (e) (e) = 2.71828, an irrational number w/ beautifully simple characteristics)
21. 21 10.2 Natural Exponential Functions and the Problem of Growth 10.2(a) The number e
10.2(b) An economic interpretation of e
10.2(c) Interest compounding and the function Aert
10.2(d) Instantaneous rate of growth
10.2(e) Continuous vs. discrete growth
10.2(f) Discounting and negative growth
22. 22 10.2(a) The number e
23. 23 10.2(b&c) Interest compounding and the function Aert y = Aert is the value of an $A investment at nominal interest rate r / compounding period compounded t times over the investment period (# days, months, or years) (growth in an investment)
As m ? ?, e ? $2.71828
$1 = initial investment
$1 = 100% return
(if m = 1 at the end of the year, then e = 2
if m > 1, then r = 100% is a nominal rate and e > 2)
$.71828 = interest on the interest received during the year as m ? ?, r = 171.8% (effective rate)
24. 24 10.2(e) Continuous vs. discrete growth
25. 25 10.2(e) Continuous vs. discrete growth
26. Relation between effective (i) and nominal (r) rates of interest 26
27. 27 10.2(d) Instantaneous rate of growth of a stock at two points in time (Chiang, pp. 278-289)
28. 28 10.2(d) Instantaneous rate of growth of a stock at two points in time (Chiang, pp. 278-289)
29. 29
30. 30 10.2(f) Discounting as negative growth or rate of decay
future V= present A= f(compounding the present A) f(discounting the future V)
31. 31 10.3 Logarithms 10.3(a) The meaning of logarithm
10.3(b) Common log and natural log
10.3(c) Rules of logarithms
10.3(d) An application
32. 32 10.3(a) The meaning of logarithm Exponents Common logs
(solve for y given t) (solve for t given y)
33. 33 10.3(b) Common log and natural log Exponent Natural log
34. 34 10.3(c) Rules of logarithms in the land of exponents Product
Quotient
Power
Base inversion
Base conversion
35. 35 10.4 Logarithmic Functions 10.4(a) Log functions and exponential functions
10.4(b) The graphical form
10.4(c) Base conversion
36. 36 10.4(a) Log functions and exponential functions Exponential function Log function
Dependent variable on left
Monotonically increasing functions
If ln y1 = ln y2, then y1 = y2
37. 37 10.4(b) The graphical formy=et (blue), y=2t (red-top), y=ln(t) (red), 45o (green)
38. 38 10.4(c) Base conversion Let er = bc
Then ln er = ln bc
r = ln bc = c ln b
Therefore
er = e c ln b
And
y = Abct = Ae(c ln b)t =Aert
39. 39
40. 40
41. 41 10.5 Derivatives of Exponential and Logarithmic Functions 10.5(a) Log-function rule
10.5(b) Exponential-function rule
10.5(c) The rules generalized
10.5(d) The case of base b
10.5(e) Higher derivatives
42. 10.5 Derivative of y=ln t 42
43. 43 10.5(a) Log-function rule Derivative of a log function with base e
Simple General
44. 44 10.5(b) Exponential-function rule Derivative of an exponential function with base e
Simple General
45. 45 10.3(d) An application The common use of the logarithmic transformation in economic research is when estimating production functions and other multiplication nonlinear theoretical specifications
Transforming a multiplicative production function into a logarithmic one suitable for estimation by linear regression. Let Q = output and L & K are labor and capital inputs respectively
46. 46 Total differential of Q using logs
47. Exponent example 47
48. 48
49. 49 10.5(d) The case of base b
50. 50 10.5(e) Higher derivatives
51. 51 10.6 Optimal Timing 10.6(a) A problem of wine storage
10.6(b) Maximization conditions
10.6(c) A problem of timber cutting
52. 10.6(a) A problem of wine storage
53. 53 10.6(a) A problem of wine storage
54. 54 10.6(b) Maximization conditions
55. 55 10.6(a) A problem of wine storage plot of .5(t)-.5=r, r=.10, t=25
56. 56
57. 57
58. 58 10.6(c) Timber cutting problemplot of .5(t)-.5ln(2)=r, r=.05, t=48
59. 59 10.7 Further Applications of Exponential and Logarithmic Derivatives 10.7(a) Finding the rate of growth
10.7(b) Rate of growth of a combination of functions
10.7(c) Finding the point elasticity
60. 60 10.7(a) Finding the rate of growth
61. 61 10.7(b) Rate of growth of a combination of functions; Example 3 consumption & pop.
62. 62 10.7(b) Rate of growth of a combination of functions; Example 3 consumption & pop.
63. 63 10.7(c) Finding the point elasticity
64. 64
65. 65