Math 121 Practice Exam III
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(1)
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A function f is said to be odd provided f(-x) = - f(x) for all x in
the domain of f. Which of the following functions are odd?
| (a) f(x) = x3 - 2x |
(b) g(t) = t2 + 3t |
(c) h(z) = z5 + z1/3 |
| (d) u(y) = y4 |
(e) w(a) = a-3/5 |
(f) q(r) = r3 + r - 1 |
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(2)
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A function f is said to be even provided f(-x) = f(x) for all x in
the domain of f. Which of the following functions are even?
| (a) f(x) = x5 |
(b) g(t) = t4 - 3t + 2 |
(c) h(z) = z4 - z2 + 10 |
| (d) u(y) = [Ö((y2
+ 1))] |
(e) w(a) = 2 + a-4/3 |
(f) q(r) = 2 |
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(3)
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Choose any of the odd functions above. If you translate this function one
unit left, is the resulting function still odd?
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(4)
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Choose any of the (nonconstant) even functions above. If you translate this
function one unit left, is the resulting function still even?
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(5)
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If we take an even function and translate it vertically one unit, is the
resulting function still even? Justify your answer.
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(6)
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If we take an odd function and translate it vertically one unit, is the resulting
function still odd? Justify your answer.
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(7)
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Explain why the function y = 0 is both even and odd. Is this true for any
other constant function?
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(8)
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Explain why an even function cannot be invertible.
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(9)
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Suppose that f is an odd invertible function. Is the inverse of f also odd?
Justify your answer.
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(10)
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Let f(x) = x2 - 3x + 1. Find a formula for h(x) = f(x+1) +3. Without
sketching either the graph of f or h, what can we say about how these graphs
compare?
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(11)
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Find a formula for the function h which is obtained from f(x) =
Öx by first scaling by a factor of -1/2, then
translating 5 units down and 4 units left.
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Figure 1
Figure 2
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(12)
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The graph in Figure 1 above is a scaled and translated version of f(x) =
[1/x]. Find a formula for this function.
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(13)
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The graph in Figure 2 above is a scaled and translated version of f(x) =
x3. Find a formula for this function.
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(14)
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If f(x) = x3 - 2, find a formula for f -1 as a function
of the output variable y.
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(15)
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If g(t) = 5(x-2)1/5, find a formula for g -1 as a function
of the output variable y.
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(16)
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Graphs of functions f and g are given below. The symbol
f°g stands for the composition y = f(g(x)).
On the grid provided, sketch the graphs of
f°g and g°f.
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(17)
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Let f(x) = x2 - x + 1 and let g(u) = u + 5. Find formulas for
f°g and g°f.
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(18)
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Let f(t) = [Ö(t - 1)] and let g(z) = [1/z].
Find formulas for f°g and
g°f.
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(19)
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Show that f(x) = x1/5 - 3 and g(x) = (x+3)5 are inverses
of each other.
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(20)
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Show that f(x) = 8(x-1)3 and g(x) = [(x1/3)/2] + 1
are inverses of each other.
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(21)
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On the grids provided in Figures 3 and 4 below, reflect the graphs of f and
g about the line y = x. Explain why the resulting graphs prove f has and
inverse while g does not.
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Figure 3
Figure 4
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(22)
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The graph of a function f is shown below. On the same grid, sketch the graph
of f -1.
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(23)
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Let f and g be functions. In your own words, describe the difference between
the functions fg and f°g.
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(24)
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Let f(x) = Log(x) and g(x) = x2 - 1. Find formulas for f+g, g/f,
f/g, fg, and f°g.