Chapter 2 – Analyzing Polynomial and Rational Functions Answer Key 2.1 Methods for Solving Quadratic Functions Answers 1. a) standard form b) vertex form c) factored form. 2. x = {7, -2} 3. x = 2 4. x = {-1/2, -3/2} 5. , 6. x = {4, -4} 7. , 8. An equation with a power of 4 can often be FOILed and you can then solve each binomial and get your answers for the equation. So it is possible to use quadratic methods on an equation with a power of 4. 9. x = {2, 4} 10 x = {4, 8} 11. x = {2, -4} 12. 13. 14. 15. 16. The discriminant is positive 17. The discriminant is zero 18. The discriminant is negative. 2.2 Graphs of Quadratic Functions Answers 1. The graph of a quadratic is a parabola 2. A parabola opens up if is positive
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Chapter 2 – Analyzing Polynomial and Rational Functions
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Chapter 2 – Analyzing Polynomial and Rational Functions AnswerKey2.1 Methods for Solving Quadratic Functions
Answers1. a) standard form
b) vertex formc) factored form.
2. x = {7, -2}3. x = 24. x = {-1/2, -3/2}
5. , 6. x = {4, -4}
7. , 8. An equation with a power of 4 can often be FOILed and you can then solve eachbinomial
and get your answers for the equation. So it is possible to use quadratic methods on anequation with a power of 4.
9. x = {2, 4}10 x = {4, 8}11. x = {2, -4}
12.
13.
14.
15. 16. The discriminant is positive17. The discriminant is zero18. The discriminant is negative.
2.2 Graphs of Quadratic Functions
Answers1. The graph of a quadratic is a parabola2. A parabola opens up if is positive
2. A parabola opens up if is positive3. If the coefficient of is positive in , the parabola opens right4. The vertex is the extreme point of a parabola5. The line of symmetry divides a parabola in two symmetrical parts6. The graph is a parabola with the vertex at (0, 3)7. The parabola opens down, with the vertex at (2, 0)8. The parabola opens up, is narrower than the reference, and has a vertex at (-2, -8)9. a) The parabola opens down b) The vertex is at (-1, 2) c) It is not stretched10. is the narrowest11.
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15.
16. Maximum height is 11.25yds17. At max height, the ball is 15yds down the field18.
19. By approximating the vertex (15, 11)
2.3 Graphs of Polynomials Using Transformations
Answers1. a)
b) 4th degree polynomialc) 7
2. Shift up 33. Shift up 44. Shift up 65. Vertical compression (horizontal stretch) by factor of 106. Function should resemble
Graph of function should resemble: , ,
Graph of function should resemble:
Step 1: , Step 2: , Step 3: , Step 4: 9. Reflected over -axis10. Reflected over -axis11. Vertical and horizontal compression12. Horizontal and vertical translation
2.4 Graphs of Polynomials Using Zeroes
Answers1. -intercept2. the original polynomial3. The zeroes (-intercepts) are 0, 2, and 34. There are 4 intercepts5. The leading term is6. -intercepts: (-1, 0) and (3, 0) : -intercept: (0, 6)
Answers1. The numerator is a higher degree than the denominator.2. 3. 4. 5. 6.
6. 7. 8. 9. 10.
11.
12.
13.
14.
The and -intercepts are both at (0, 0)There is a vertical asymptote atThe slant asymptote is
15.
and intercept at (0, 0)Vertical asymptote atSlant asymptote at
2.7 Graphs of Rational Functions
Answers1. A point of discontinuity 2. Polynomial graphs are continuous as a rule, rational graphs the opposite 3. Holes and/or asymptotes 4. Simplifying the fraction hides the discontinuities
5. Correct order:
a. Factor numerator and denominator completely and put in lowest terms. Identifyany holes.
b. Find all intercepts.c. Find all asymptotes.c. Determine the behavior around the vertical asymptotes using a table of signs.e. Find the places where the function crosses the horizontal asymptote/oblique
asymptote.f. Sketch a smooth graph based on the above information.
6. =
7. -intercepts of are (-4, 0) and (2, 0) – there are no -intercepts, since the -axis is thevertical asymptote. There is a slant asymptote at . End behavior: as and as .
8. The domain is all real numbers except for 0. The graph looks like:
9. The function simplifies as: There is a discontinuity at x = 3, an asymptote at and another atThe function looks similar to #8, except the curves stay entirely in QII and QIV
10. The function simplifies as: There is a discontinuity atThe graph looks like the line
11. Discontinuity at , the graph is quadratic 12. Discontinuity at , the graph is linear 13. Discontinuities at and , the graph is linear
14.
15 The function simplifies to: Vertical asymptotes are atSlant asymptote atGraph looks like:
Graph looks like:
2.8 Analysis of Rational Functions
Answers
1. : x ≠ 2
2. y = : x ≠ 4
3. f(x) = : x ≠ 4
4. f(x) = : x ≠ -4/5
5. y = : x ≠ -7 6. Asymptotes: and (not required to show)
b) The total resistance will always be less than 20 because is the horizontal asymptote of
18. Width must be greater than 4 meters, .
2.11 Synthetic Division of Polynomials
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2.11 Synthetic Division of Polynomials
Answers
1.
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Factored polynomial:
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2.12 Real Zeros of Polynomials
Answers
a) 21b) 31c) 10d) 66e) TO BE REVISED (Could not find any roots for the polynomial f(x)
k = -10a)
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1.2.3.4.5.
6.7.
b)8.
a)
2.13 Intermediate Value Theorem
Answers
9.
10.11.12.13.14.b)15.
16.
Answers1. a) L.C. = 3 Degree = 5 b) 1 Real Zero c) 4 ImaginaryZeroes2. a) L.C. = -1 Degree = 3 b) 1 Real Zero c) 2 ImaginaryZeroes3. a) L.C. = 1/2 Degree = 4 b) 2 Real Zeroes c) 2 Imaginary Zeroes4. a) L.C. = -3/2 Degree = 6 b) 0 Real Zeroes c) 6 Imaginary Zeroes5. a) L.C. = 1 Degree = 5 b) 3 Real Zeroes c) 2 Imaginary Zeroes6. a) L.C. = 1 Degree = 4 b) 3 Real Zeroes c) 1 Imaginary Zero7. There is a zero in [-2, -1]8. There is a zero in [-1, 0] and [2, 3]9. There is a zero in [-2, -1], [-1, 0], [0, 1], and [3, 4]10. There is a zero in [-2, -1] and [1, 2]11. There is a zero in [-2, -1], [-1, 0], [0, 1] and [1, 2]
12. has a vertical asymptote at , so it is not continuous in theinterval . Therefore we cannot use the Bounds on Zeros theorem to claim thereis a zero in that interval.
13. The zero is in [0.3125, 0.34825]14. The zero is in [1.5000, 1.5625]15. Zero is in the interval: [0.8125, 0.875]