ESSENTIAL CALCULUS CH05 Inverse functions
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ESSENTIAL CALCULUS CH05 Inverse functions. In this Chapter:. 5.1 Inverse Functions 5.2 The Natural Logarithmic Function 5.3 The Natural Exponential Function 5.4 General Logarithmic and Exponential Functions 5.5 Exponential Growth and Decay 5.6 Inverse Trigonometric Functions
ESSENTIAL CALCULUS CH05 Inverse functions
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In this Chapter: • 5.1 Inverse Functions • 5.2 The Natural Logarithmic Function • 5.3 The Natural Exponential Function • 5.4 General Logarithmic and Exponential Functions • 5.5 Exponential Growth and Decay • 5.6 Inverse Trigonometric Functions • 5.7 Hyperbolic Functions • 5.8 Indeterminate Forms and 1’Hospital’s Rule Review
▓In the language of inputs and outputs, Definition 1 says that f is one-to-one if each output corresponds to only one input. FIGURE 2 This function is not one-to-one because f(x1)=f(x2). Chapter 5, 5.1, P247
FIGURE 3 ƒ=(x)=x2 is one-to-one. Chapter 5, 5.1, P247
FIGURE 4 g(x)=x2 is not one-to-one. Chapter 5, 5.1, P247
1. DEFINITION A function f is called a one-to-one function if it never takes on the same value twice; that is, F(x1)≠f(x2) whenever x1≠x2 Chapter 5, 5.1, P247
HORIZONTAL LINE TEST A function is one-to-one if and only if no horizontal line intersects its graph more than once. Chapter 5, 5.1, P247
FIGURE 6 The inverse function reverses inputs and outputs. Chapter 5, 5.1, P248
domain of f-1=range of f range of f-1=domain of f Chapter 5, 5.1, P248
Do not mistake the -1 in f-1 for an exponent. Thus f-1(x) does not mean Chapter 5, 5.1, P248
f-1(f(x))=x for every x in A f(f-1(x))=x for every x in B Chapter 5, 5.1, P248
5.HOW TO FIND THE INVERSE FUNCTION OF A ONE-TO-ONE FUNCTION f STEP 1 Write =f(x). STEP 2 Solve this equation for x in terms of y (if possible). STEP 3 To express f-1 as a function of x, interchange x and y. The resulting equation is y=f-1(x). Chapter 5, 5.1, P249
The graph of f-1 is obtained by reflecting the graph of f about the line y=x. Chapter 5, 5.1, P250
6.THEOREM If f is a one-to-one continuous function defined on an interval, then its inverse function f-1 is also continuous. Chapter 5, 5.1, P251
7. THEOREM If f is a one-to-one differentiable function with inverse function f-1 and f’(f-1(a))≠0, then the inverse function is differentiable at a and Chapter 5, 5.1, P251
18. The graph of f is given. (a) Why is f one-to-one? (b) What are the domain and range of f-1? (c) What is the value of f-1(2)? (d) Estimate the value of f-1(0) . Chapter 5, 5.1, P253
29–30 ■ Use the given graph of f to sketch the graph of f-1. Chapter 5, 5.1, P253
1.DEFINITION The natural logarithmic function is the function defined by ln x>0 Chapter 5, 5.2, P254
3.LAWS OF LOGARITHMS If x and y are positive numbers and r is a rational number, then 1. ln(xy)=ln x+ ln y 2. ln( )=ln x-ln y 3. ln (xr)=r ln x Chapter 5, 5.2, P255
(a) ln x=∞ (b) ln x=-∞ Chapter 5, 5.2, P256
5. DEFINITION eis the number such that . ln e=1. Chapter 5, 5.2, P257
STEPS IN LOGARITHMIC IFFERENTIATION • Take natural logarithms of both sides of an • equation y=f(x) and use the Laws of Logarithms to simplify. • 2. Differentiate implicitly with respect to x. • 3. Solve the resulting equation for y’. Chapter 5, 5.2, P260
and Chapter 5, 5.3, P262
x>0 Chapter 5, 5.3, P263
for all x Chapter 5, 5.3, P263
6. PROPERTIES OF THE NATURAL EXPONENTIAL FUNCTION The exponential function f(x)=ex is an increasing continuous function with domain R and range(0,∞) . Thus, ex>0 for all x. Also So the x-axis is a horizontal asymptote of f(x)=ex Chapter 5, 5.3, P264