EXAMPLE 1Identifying Maximum and Minimum Values and Local Extreme Values from the Graph of a Function
Figures 10, 11, 12, 13, 14 and 15 show the graphs of six different functions. For each function:
Continuity is discussed in Section 1.3, pp. 93-102.
- (a) Find the domain.
- (b) Determine where the function is continuous.
- (c) Identify the absolute maximum value and the absolute minimum value, if they exist.
- (d) Identify any local extreme values.
Solution
Figure 10 (a) Domain: [0,3π2]
(b) Continuous on [0,3π2]
(c) Absolute maximum value:
f(0)=1
Absolute minimum value:
f(π)=−1
(d) No local maximum value;
local minimum value: f(π)=−1
Figure 11 (a) Domain: (−1,3)
(b) Continuous on (−1,3)
(c) Absolute maximum value:
f(0)=1
Absolute minimum value:
f(2)=−7
(d) Local maximum value:
f(0)=1
Local minimum value:
f(2)=−7
Figure 12 (a) Domain: (−1,4]
(b) Continuous on (−1,4]
(c) No absolute maximum value;
absolute minimum value:
f(4)=1
(d) No local maximum value;
no local minimum value
Figure 13 (a) Domain: (0,e)
(b) Continuous on (0,e)
(c) No absolute maximum value;
no absolute minimum value
(d) No local maximum value;
no local minimum value
Figure 14 (a) Domain: [0,6]
(b) Continuous on [0,6] except
at x=2
(c)Absolute maximum value:
f(2)=6
Absolute minimum value:
f(6)=−2
(d) Local maximum value: f(2)=6
Local minimum value: f(1)=0
Figure 15 (a) Domain: [−2,2]
(b) Continuous on [−2,2] except at x=0
(c) Absolute maximum value:
f(−2)=3, f(2)=3
No absolute minimum value
(d) Local maximum value: f(0)=2
No local minimum value
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