Show full work. Β HW 3.1-3.4 and 3.5-3.7
Math 3βCollege Algebra
HW 3.1β3.4
Name: ______________________
Show all your work for full credit:
3.1 Quadratic Functions and Models
Q1. The graph of π(π₯) = 3(π₯ β 2)2 β 6 is a parabola that opens _________, with its vertex at
( _____, _____) , and π(2) = ____________ is the ( minimum/ maximum) ___________ value
of π.
Q2βQ4. A quadratic function π is given. (a) Express π in standard form. (b) Find its vertex, π₯ β
πππ‘ππππππ‘(π ) and π¦ β πππ‘ππππππ‘ of π. (c) sketch the graph of π (d) Find the domain and range
of π.
Q2. π(π₯) = 2π₯ 2 + 4π₯ + 3
Q3. π(π₯) = 2π₯ 2 β 20π₯ + 57
Q4. π(π₯) = β4π₯ 2 β 12π₯ + 1
Q5βQ7. A quadratic function π is given. (a) Express π in standard form. (b) sketch a graph of
π. (c) Find the maximum or minimum value of π.
Q5. π(π₯) = 3π₯ 2 β 6π₯ + 1
Q6. π(π₯) = βπ₯ 2 β 3π₯ + 3
Q7. π(π₯) = 3π₯ 2 β 12π₯ + 13
Q8βQ9. Find the maximum and minimum value of the function.
Q8. π(π‘) = β3 + 80π‘ β 20π‘ 2
1
Q9. β(π₯) = 2 π₯ 2 + 2π₯ β 6
Q10. If a ball is thrown directly upward with a velocity of 40 ππ‘/π , its height ( in feet) after π‘
seconds is given by π¦ = 40π‘ β 16π‘ 2 . What is the maximum height attained by the ball?
1
3.2 Polynomial Functions and their graphs
Q1βQ4. Sketch the graph of the polynomial function. Make sure your graphs shows all
intercepts and exhibits the proper end behavior.
Q1. π(π₯) = βπ₯( π₯ β 3)(π₯ + 2)
Q2. π(π₯) = (π₯ + 2)(π₯ + 1)(π₯ β 2)(π₯ β 3)
Q3. π(π₯) = β2π₯( π₯ β 2)2
Q4. π(π₯) = π₯ 3 (π₯ + 2)(π₯ β 3)2
Q5βQ9. Factor the polynomial and use the factored form to find the zeros. Then sketch the
graph.
Q5. π(π₯) = π₯ 3 β π₯ 2 β 6π₯
Q6. π(π₯) = π₯ 4 β 3π₯ 3 + 2π₯ 2
Q7. π(π₯) = 2π₯ 3 β π₯ 2 β 18π₯ + 9
Q8. π(π₯) = π₯ 4 β 2π₯ 3 β 8π₯ + 16
Q9. π(π₯) = βπ₯ 3 + π₯ 2 + 12π₯
2
3.3 Dividing Polynomials
Q1. Two polynomials P and D are given. Use synthetic and long division to divide π(π₯) by
π(π₯)
π
(π₯)
π·(π₯), and express the quotient π(π₯)/π·(π₯) in the form
=
π(π₯)
+
π·(π₯)
π·(π₯)
Q1. π(π₯) = 2π₯ 2 β 5π₯ β 7
π·(π₯) = π₯ β 2
Q2βQ4. Find the quotient and remainder using synthetic division.
Q2.
2π₯ 2 β5π₯+3
π₯β3
Q3.
π₯ 3 β8π₯+2
π₯+3
Q4.
2π₯ 3 +3π₯ 2 β2π₯+1
π₯β
1
2
Q5βQ7. Use synthetic division and the Remainder Theorem to evaluate π(π).
Q5. π(π₯) = 4π₯ 2 + 12π₯ + 5, π = β1
Q6. π(π₯) = π₯ 7 β 3π₯ 2 β 1, π = 3
Q7. π(π₯) = π₯ 3 + 2π₯ 2 β 3π₯ β 8, π = 0.1
Q8βQ9. Use the Factor Theorem to show that π₯ β π is a factor of π(π₯) for the given value(s) of
c.
Q8. π(π₯) = π₯ 3 β 3π₯ 2 + 3π₯ β 1, π = 1
1
Q9. π(π₯) = 2π₯ 3 + 7π₯ 2 + 6π₯ β 5, π = 2
Q10βQ11. Show that the given value(s) of c are zeros of π(π₯), and find all other zeros of π(π₯).
Q10. π(π₯) = π₯ 3 + 2π₯ 2 β 9π₯ β 18, π = β2
Q11. π(π₯) = 3π₯ 4 β 8π₯ 3 β 14π₯ 2 + 31π₯ + 6, π = β2, 3
Q12—Q13. Find a polynomial of the specified degree that has the given zeros.
Q12. Degree 3; zeros β1, 1, 3
Q13. Degree 4, zeros β1, 1, 3, 5
3
3.4 Real zeros of polynomials
Q1—Q2. List all possible rational zeros given by the Rational zeros Theorem (but donβt check to
see which actually are zeros).
Q1. π
(π₯) = 2π₯ 5 + 3π₯ 3 + 4π₯ 2 β 8
Q2. π(π₯) = 4π₯ 4 β 2π₯ 2 β 7
Q3βQ6. Find all the real zeros of the polynomial and write the polynomial in factored form.
Q3. π(π₯) = π₯ 4 β 5π₯ 2 + 4
Q4. π(π₯) = 4π₯ 3 + 4π₯ 2 β π₯ β 1
Q5. π(π₯) = 4π₯ 3 β 6π₯ 2 + 1
Q6. π(π₯) = 2π₯ 4 + 15π₯ 3 + 17π₯ 2 + 3π₯ β 1
Q7βQ8. A polynomial P is given, (a) Find all the real zeros of P (b) sketch a graph of P.
Q7. π(π₯) = π₯ 3 β 3π₯ 2 β 4π₯ + 12
Q8. π(π₯) = π₯ 4 β 5π₯ 3 + 6π₯ 2 + 4π₯ β 8
Q9βQ10. Use Descartesβ Rule of Signs to determine how many positive and how many
negative real zeros of the polynomial can have. Then determine the possible total number of real
zeros.
Q9. π(π₯) = 2π₯ 6 + 5π₯ 4 β π₯ 3 β 5π₯ β 1
Q10. π(π₯) = π₯ 5 + 4π₯ 3 β π₯ 2 + 6π₯
Q11βQ12. Show that the given values for a and b are lower and upper bounds for the real zeros
of the polynomial.
Q11. π(π₯) = 2π₯ 3 + 5π₯ 2 + π₯ β 2
π = β3, π = 1
Q12. π(π₯) = π₯ 4 + 2π₯ 3 + 3π₯ 2 + 5π₯ β 1
π = β2, π = 1
Q13βQ14. Find all rational zeros of the polynomial, and then find the irrational zeros, if any.
Whenever appropriate, use the Rational Zeros Theorem, the Upper and Lower Bounds Theorem,
Descartesβ Rule of Signs, the Quadratic Formula, or other factoring techniques.
Q13. π(π₯) = 2π₯ 4 + 3π₯ 3 β 4π₯ 2 β 3π₯ + 2
Q14. π(π₯) = 4π₯ 4 β 21π₯ 2 + 5
4
Math 3βCollege Algebra
HW 3.5β3.7
Name: ______________________
3.5 Complex zeros and the Fundamental Theorem of Algebra
Q1—Q3. A polynomial P is given. (a) Find all zeros of P, real and complex (b) Factor P
completely.
Q1. π(π₯) = π₯ 4 + 4π₯ 2
Q2. π(π₯) = π₯ 3 β 2π₯ 2 + 2π₯
Q3. π(π₯) = π₯ 3 + 8
Q4βQ6. Factor the polynomial completely and find all its zeros. State the multiplicity of each
zero.
Q4. π(π₯) = π₯ 4 + 2π₯ 2 + 1
Q5. π(π₯) = π₯ 3 + π₯ 2 + 9π₯ + 9
Q6. π(π₯) = π₯ 5 + 6π₯ 3 + 9π₯
Q7—Q10. Find a polynomial with integer coefficients that satisfies the given conditions.
Q7. π βππ ππππππ 2 πππ π§ππππ 1 + π πππ 1 β π
Q8. P has degree 3 and zeros 2 and π.
Q9. R has degree 4 and zeros 1 β 2π and 1, with 1 a zero of multiplicity 2.
Q10. T has degree 4, zeros π and 1 + π, and constant term 12.
Q11βQ13. Find all zeros of the polynomial.
Q11. π(π₯) = π₯ 3 + 2π₯ 2 + 4π₯ + 8
Q12. π(π₯) = 2π₯ 3 + 7π₯ 2 + 12π₯ + 9
Q13. π(π₯) = π₯ 4 + π₯ 3 + 7π₯ 2 + 9π₯ β 18
1
3.6 Rational Functions
Q1βQ10. Graph the rational function. Show clearly all π₯ β πππ‘ππππππ‘(π ) and π¦ β
πππ‘ππππππ‘(π ), asymptotes, and state the domain and range of π.
5
Q1. π(π₯) = π₯β2
Q3. π(π₯) =
4π₯β4
π₯+2
2π₯β4
Q5. π(π₯) = π₯ 2 +π₯β2
Q7. π(π₯) =
Q9. π(π₯) =
π₯ 3 +27
π₯+4
π₯ 2 +4π₯β5
π₯ 2 +π₯β2
Q2. π(π₯) =
Q4. π(π₯) =
2π₯β3
π₯β2
3π₯ 2 β12π₯+13
π₯ 2 β4π₯+4
(π₯β1)(π₯+2
Q6. π(π₯) = (π₯+1)(π₯β3)
Q8. π(π₯) =
Q10. π(π₯) =
2
π₯ 2 +2
π₯β1
π₯ 2 β2π₯β3
π₯+1
3.7 polynomial and rational inequalities
Q1βQ10. Solve the inequality.
Q1. 2π₯ 2 β₯ π₯ + 3
Q2. (π₯ β 3)(π₯ + 5)(2π₯ + 5) < 0
Q3. π₯ 3 + 4π₯ 2 β₯ 4π₯ + 16
Q4. 2π₯ 3 β π₯ 2 < 9 β 18π₯
Q5. π₯ 4 β 7π₯ 2 β 18 < 0
π₯β1
Q6. π₯β10 < 0
2π₯+5
Q7. π₯ 2 +2π₯β35 β₯ 0
π₯β3
Q8. 2π₯+5 β₯ 1
1
3
Q9. 2 + 1βπ₯ β€ π₯
3
2.1 Functions
Q1.
π(π₯) = π₯ 2 β 6
π(β3) = (β3)2 β 6 = 9 β 6 = π
π(3) = 32 β 6 = 9 β 6 = π
π(0) = 02 β 6 = 0 β 6 = βπ
1
1 2
1
ππ
π( ) = ( ) β6 = β6 = β
2
2
4
π
1 β 2π₯
3
1 β 2(2)
= βπ
3
1 β 2(β2) π
π(β2) =
=
3
π
1
1 β 2 (2)
1
π( ) =
=π
2
3
π β ππ
π(π) =
π
1 β 2(βπ) π + ππ
π(βπ) =
=
3
π
1 β 2(π β 1) π β ππ
π(π β 1) =
=
3
π
π(π₯) = π₯ 2 + 2π₯
π(0) = 02 + 2(0) = π
π(3) = 32 + 2(3) = ππ
π(β3) = (β3)2 + 2(β3) = π
π(π) = ππ + ππ
π(βπ₯) = (βπ₯)2 + 2(βπ₯) = ππ β ππ
1
1 2
1
π + ππ
π( ) = ( ) + 2( ) =
π
π
π
ππ
Q2.
π(π₯) =
π(2) =
Q3.
Q4.
π(π₯) = {
π₯2,
π₯ + 1,
ππ π₯ < 0
ππ π₯ β₯ 0
π(β2) = (β2)2 = π
π(β1) = (β1)2 = π
π(0) = 0 + 1 = π
π(1) = 1 + 1 = π
π(2) = 1 + 1 = π
Q5.
π₯ 2 β 2π₯,
ππ π₯ β€ β1
π(π₯) = { π₯,
ππ β 1 < π₯ β€ 1
β1,
ππ π₯ β₯ 1
π(β4) = (β4)2 β 2(β4) = ππ
3
3 2
3
ππ
π (β ) = (β ) β 2 ( ) =
2
2
2
π
π(β1) = (β1)2 β 2(β1) = π
π(0) = π
π(25) = βπ
Q6.
π(π₯) =
1
π₯β3
The domain of the function is the values of x that
will not make the denominator zero.
π₯β3β 0
π·πππππ: π β π
Q7.
The domain of the function is the values of x that
will not make the radicand negative.
π(π‘) = βπ‘ + 1
π‘+1 β₯ 0
π·πππππ: π β₯ βπ
Q8.
π(π₯) = β1 β 2π₯
The domain of the function is the values of x that
will not make the radicand negative.
1 β 2π₯ β₯ 0
1 β₯ 2π₯
π·πππππ: π β€
π
π
Q9.
A linear functionβs domain is the set of real
numbers.
π·πππππ: πππΉ
π(π₯) = 3π₯
2.2 Graphs of a Function
Q1.
Since the domain is from -3 to 3, find points between -3 and 3 and connect them to draw the function.
Draw a line from -3 to 3 only! Do not extend the line!
π(π₯) = βπ₯ + 3, β3 β€ π₯ β€ 3
π₯
π(π₯)
π₯
π(π₯)
-3
6
1
2
-2
5
2
1
-1
4
3
0
0
3
Q2.
π(π₯) = βπ₯ 2
π₯
π(π₯) π₯
π(π₯)
-3
-9
1
-1
-2
-4
2
-4
-1
-1
3
-9
0
0
Q3.
π(π₯) = 1 + βπ₯
π₯
π(π₯)
π₯
π(π₯)
0
1
2
3
1
4
3
2
25
4
7
2
1
2
3
4
9
4
5
2
Q4.
π(π₯) = |2π₯|
π₯
π(π₯) π₯
π(π₯)
-3
6
1
2
-2
4
2
4
-1
2
3
6
0
0
Q5.
Take note of the hollow dot at (2,3), because the value of the function at x=2 is at y=2 and not at y=3.
π(π₯) = {
3,
π₯ β 1,
ππ π₯ < 2
ππ π₯ β₯ 2
π₯
π(π₯)
π₯
π(π₯)
-1
3
2
1
0
3
3
2
1
3
4
3
Q6.
Take note of the hollow dot at (0,1), because the value of the function at x=0 is at y=0 and not at y=1.
π(π₯) = {
π₯,
π₯ + 1,
ππ π₯ β€ 0
ππ π₯ > 0
π₯
π(π₯)
π₯
π(π₯)
-2
-2
1
2
-1
-1
2
3
0
0
3
4
Q7.
Note that there are no holes in this piecewise function.
4,
ππ π₯ < 2
π(π₯) = {π₯ 2 ,
ππ β 2 β€ π₯ β€ 2
βπ₯ + 6,
ππ π₯ > 2
π₯
π(π₯)
π₯
π(π₯)
-3
4
1
1
-2
4
2
4
-1
1
3
3
0
0
4
2
Q8.
3π₯ β 5π¦ = 7
β5π¦ = β3π₯ + 7
3
7
π¦= π₯β
5
5
The equation is a linear function in the form π(π₯) = ππ₯ + π. Thus, y is defined as a function of x.
Q9.
2π₯ β 4π¦ 2 = 4
π₯ β 2π¦ 2 = 2
β2π¦ 2 = βπ₯ + 2
π₯
π¦2 = β 1
2
π₯
π¦ = Β±β β 1
2
π₯
π₯
The equation for y is defined by two functions: β2 β 1 and ββ2 β 1. This makes the relation one-tomany. Therefore, y is NOT defined as a function of x.
Q10.
2|π₯| + π¦ = 0
π¦ = β2|π₯|
The equation is an absolute value function in the form π(π₯) = π|π₯|. Thus, y is defined as a function of x.
2.3 Getting information from the graph of a function.
Q1.
a. β(β2) = 1, β(0) = β1, β(2) = 3, β(3) = 4
b. The leftmost point of the function is at x=-3.
The rightmost point of the function is at x=4. The
domain is β3 β€ π₯ β€ 4.
The lowest point of the function is at y=-1. The
highest point of the function is at y=4. The range
is β1 β€ π¦ β€ 4.
c. Intersect the line y=3 to the function. The
values of x are where the line and function
intersect. The values are x=-3, 2, 4.
d. Intersect the line y=3 to the function. The
values of x are where the function is below or at
the line. The values are β3 β€ π₯ β€ 2.
e.
Net change is π(3) β π(β3) = 4 β 3 = 1.
Q2.
a. π(0) = 3, π(0) = 0.5. The larger value is π(0).
b. π(β3) = β1, π(β3) = 2. The larger value is
π(β3).
c. Find the values of x where the two functions
intersect. The two functions intersect at x=-2, 2.
d. Find the values of x where the red function f(x)
is below or at the blue function g(x). The values
of x are β4 β€ π₯ β€ β2 βͺ 2 β€ π₯ β€ 4.
e. Find the values of x where the red function f(x)
is above the blue function g(x). The values of x
are β2 < π₯ < 2.
Q3.
Domain: The domain of linear
functions is the set of real numbers.
π·πππππ: ππ πΉ
Range: The range of linear functions is
the set of real numbers.
π·πππππ: ππ πΉ
π(π₯) = 2π₯ + 3
Q4.
Domain: The domain is given from the
condition stated by the function.
π·πππππ: βπ β€ π β€ π
Range: The lowest point of the function
is at y=-4 and the highest point of the
function is at y=3.
π·πππππ: βπ β€ π β€ π
π(π₯) = π₯ β 2, β2 β€ π₯ β€ 5
Q5.
Domain: The domain is given from the
condition stated by the function.
π·πππππ: βπ β€ π β€ π
Range: The lowest point of the function
is at y=-1 and the highest point of the
function is at y=8.
π·πππππ: βπ β€ π β€ π
π(π₯) = π₯ 2 β 1, β3 β€ π₯ β€ 3
Q6.
a.
Domain: The leftmost point is at x=-1
and the rightmost point is at x=4. The
domain is β1 β€ π₯ β€ 4.
Range: The lowest point is at y=-1 and
the highest point is at y=3. The domain
is β1 β€ π¦ β€ 3.
b.
Increasing: The function is increasing
at β1 β€ π₯ < 1 βͺ 2 < π₯ β€ 4.
Decreasing: The function is decreasing
at 1 < π₯ < 2.
Q7.
a.
Domain: The leftmost point is at x=-3
and the rightmost point is at x=3. The
domain is β3 β€ π₯ β€ 3.
Range: The lowest point is at y=-2 and
the highest point is at y=2. The domain
is β2 β€ π¦ β€ 2.
b.
Increasing: The function is increasing
at β2 < π₯ < β1 βͺ 1 < π₯ < 2.
Decreasing: The function is decreasing
at β3 β€ π₯ < β2 βͺ β1 < π₯ < 1 βͺ 2 <
π₯ β€ 3.
Q8.
a. The graph of the function is shown.
b.
Domain: The domain of quadratic
functions is the set of real numbers.
π·πππππ: ππ πΉ
Range: Find the vertex of the function,
which is the extreme point of the
function.
π(π₯) = ππ₯ 2 + ππ₯ + π
π
β5
β=β
ββ=
= β2.5
2π
2
π(β2.5) = (β2.5)2 β 5(β2.5) = β6.25
π(π₯) = π₯ 2 β 5π₯
Since the function is an upward parabola,
the range is:
π
ππππ: π β₯ βπ. ππ
c. From the vertex and axis of symmetry
in the graph, the function is increasing at
π₯ > 2.5 and the function is decreasing at
π₯ < 2.5.
d. From the graph, the local minimum is
at (2.5, -6.25), and there is no local
maximum.
2.4 Average rate of change of a function.
Q1. π(π₯) = 3π₯ β 2, π₯ = 2, π₯ = 3
3
Q2. β(π‘) = βπ‘ + 2 , π‘ = β4, π‘ = 1
Q3. β(π‘) = 2π‘ 2 β π‘, π‘ = 3, π‘ = 6
Q4. π(π₯) = π₯ 3 β 4π₯ 2 , π₯ = 0, π₯ = 10
1
π₯
Q5. π(π₯) = , π₯ = 1, π₯ = π
π(2) = 3(2) β 2 = 4
π(3) = 3(3) β 2 = 7
πππ‘ πβππππ = π(3) β π(2) = 3
πππ‘ πβππππ
π΄π£πππππ πππ‘π =
=3
3β2
3
β(β4) = 4 + = 5.5
2
3
β(1) = β1 + = 0.5
2
πππ‘ πβππππ = β(1) β β(β4) = β5
πππ‘ πβππππ
π΄π£πππππ π
ππ‘π =
= β1
1 β (β4)
β(3) = 2(3)2 β 3 = 15
β(6) = 2(6)2 β 6 = 66
πππ‘ πβππππ = β(6) β β(3) = 51
πππ‘ πβππππ
π΄π£πππππ π
ππ‘π =
= 17
6β3
3
2
π(0) = 0 β 4(0) = 0
π(10) = 103 β 4(10)2 = 600
πππ‘ πβππππ = π(10) β π(0) = 600
πππ‘ πβππππ
π΄π£πππππ π
ππ‘π =
= 60
10 β 0
1
π(1) = = 1
1
1
π(π) =
π
1
1βπ
πππ‘ πβππππ = π(π) β π(1) = β 1 =
π
π
1βπ
πππ‘ πβππππ
1
π΄π£πππππ πππ‘π =
= π =β
πβ1
πβ1
π
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