AP Precalculus -1.11 Equivalent Forms of Polynomial and Rational Expressions- MCQ Exam Style Questions - Effective Fall 2023
AP Precalculus -1.11 Equivalent Forms of Polynomial and Rational Expressions- MCQ Exam Style Questions – Effective Fall 2023
AP Precalculus -1.11 Equivalent Forms of Polynomial and Rational Expressions- MCQ Exam Style Questions – AP Precalculus- per latest AP Precalculus Syllabus.
Question
(B) \( h \) is equivalent to \( \frac{2x^3 – 4}{x^2 + 2x – 3} \) and has the same end behavior as the graph of \( y = 2x \).
(C) \( h \) is equivalent to \( \frac{2x^3}{x} + \frac{2x^2}{3} – \frac{4}{x-1} \) and has the same end behavior as the graph of \( y = 2x^2 \).
(D) \( h \) is equivalent to \( \frac{2x^2 – 2x – 12}{3x – 3} \) and has the same end behavior as the graph of \( y = 2x \).
▶️ Answer/Explanation
First, combine into a single fraction:
Common denominator: \((x+3)(x-1) = x^2 + 2x – 3\).
\[ h(x) = \frac{2x^3}{x+3} – \frac{4}{x-1} = \frac{2x^3(x-1) – 4(x+3)}{(x+3)(x-1)}. \]
Simplify numerator:
\[ 2x^3(x-1) – 4(x+3) = 2x^4 – 2x^3 – 4x – 12. \]
So \( h(x) = \frac{2x^4 – 2x^3 – 4x – 12}{x^2 + 2x – 3} \).
For end behavior: degree(numerator) = 4, degree(denominator) = 2, so as \( x \to \pm\infty \),
\[ h(x) \approx \frac{2x^4}{x^2} = 2x^2. \]
Thus \( h \) has the same end behavior as \( y = 2x^2 \).
✅ Answer: (A)
Question
(B) \( x^4 + 4x^3 + 6x^2 + 4x + 1 \)
(C) \( x^4 + 8x^3 + 24x^2 + 32x + 16 \)
(D) \( 2x^4 + 8x^3 + 12x^2 + 8x + 2 \)
▶️ Answer/Explanation
Using binomial expansion or Pascal’s Triangle for \( (x + 2)^4 \):
\( (x + 2)^4 = \sum_{k=0}^4 \binom{4}{k} x^{4-k} \cdot 2^{k} \)
\( = \binom{4}{0}x^4\cdot 2^0 + \binom{4}{1}x^3\cdot 2^1 + \binom{4}{2}x^2\cdot 2^2 + \binom{4}{3}x^1\cdot 2^3 + \binom{4}{4}x^0\cdot 2^4 \)
\( = 1\cdot x^4 \cdot 1 + 4\cdot x^3\cdot 2 + 6\cdot x^2\cdot 4 + 4\cdot x \cdot 8 + 1\cdot 1\cdot 16 \)
\( = x^4 + 8x^3 + 24x^2 + 32x + 16 \).
✅ Answer: (C)
Question
(B) The remainder of \(\frac{f(x)}{x+3}\) is 0. The quotient of \(\frac{f(x)}{x+3}\) is a quadratic polynomial that does not factor into linear factors involving only real numbers.
(C) The remainder of \(\frac{f(x)}{x+3}\) is a nonzero constant. The quotient of \(\frac{f(x)}{x+3}\) is a quadratic polynomial that factors into two linear factors involving only real numbers.
(D) The remainder of \(\frac{f(x)}{x+3}\) is a nonzero constant. The quotient of \(\frac{f(x)}{x+3}\) is a quadratic polynomial that does not factor into linear factors involving only real numbers.
▶️ Answer/Explanation
We can check if \(x+3\) is a factor by evaluating \(f(-3)\):
\(f(-3) = 2(-27) – 3(9) – 23(-3) + 12 = -54 – 27 + 69 + 12 = 0\).
So \(x+3\) divides \(f\) with remainder 0.
Perform polynomial division: \( (2x^3 – 3x^2 – 23x + 12) \div (x+3) \) yields \( 2x^2 – 9x + 4 \).
Now factor \( 2x^2 – 9x + 4 \): it factors into \((2x – 1)(x – 4)\), both linear factors with real coefficients.
Thus: remainder is 0, quotient is quadratic and factors into real linear factors.
✅ Answer: (A)
Question
(B) \( b \)
(C) \( c \)
(D) \( d \)
▶️ Answer/Explanation
Expand \( (x + 3)^4 \) using binomial theorem:
\( (x + 3)^4 = x^4 + 4\cdot 3\cdot x^3 + 6\cdot 3^2\cdot x^2 + 4\cdot 3^3\cdot x + 3^4 \)
\( = x^4 + 12x^3 + 54x^2 + 108x + 81 \).
So \( a = 12,\; b = 54,\; c = 108,\; d = 81 \).
Greatest is \( c = 108 \).
✅ Answer: (C)
Question
▶️ Answer/Explanation
The binomial expansion of \((x + 3y)^5\) is found using the formula \((a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k\), with \(n=5\).
The binomial coefficients for the 5th power (Row 5 of Pascal’s Triangle) are \(1, 5, 10, 10, 5, 1\).
The correct theoretical expansion is: \(1(x)^5 + 5(x)^4(3y)^1 + 10(x)^3(3y)^2 + 10(x)^2(3y)^3 + 5(x)^1(3y)^4 + 1(3y)^5\).
We compare this pattern with the given options by checking the coefficients.
Option (A) is missing terms, Option (B) has incorrect coefficients (all are \(1\)), and Option (C) uses coefficients for \(n=4\) (\(1, 4, 6, 4, 1\)).
Option (D) correctly matches the coefficients \(1, 5, 10, 10, 5, 1\). Note that while the question image contains typographical errors in the exponents, (D) is the only option with the correct binomial structure.
Therefore, the correct option is (D).
Question
▶️ Answer/Explanation
The general binomial expansion is given by the formula: \((a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k\).
In this problem, we identify the values as \(a = x\), \(b = 3y\), and the exponent \(n = 5\).
The binomial coefficients for the power of 5 (from Pascal’s triangle) are: \(1, 5, 10, 10, 5, 1\).
We apply these coefficients to the decreasing powers of \(x\) and increasing powers of \((3y)\).
The expansion becomes: \(1(x)^5 + 5(x)^4(3y) + 10(x)^3(3y)^2 + 10(x)^2(3y)^3 + 5(x)(3y)^4 + 1(3y)^5\).
Comparing this expanded form with the given choices, it corresponds exactly to Option (D).
Question
▶️ Answer/Explanation
The correct option is (C).
1. According to the Binomial Theorem, \((a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k\).
2. Identify the components for substitution: \(a = x\), \(b = -4y\), and \(n = 5\).
3. The binomial coefficients for \(n=5\) (from Pascal’s triangle) are: \(1, 5, 10, 10, 5, 1\).
4. Substitute these into the formula: \(1(x)^5 + 5(x)^4(-4y) + 10(x)^3(-4y)^2 + 10(x)^2(-4y)^3 + 5(x)(-4y)^4 + 1(-4y)^5\).
5. Simplify the signs: odd powers of \((-4y)\) result in a negative sign, while even powers result in a positive sign.
6. The final expansion is: \(x^5 – 5x^4(4y) + 10x^3(4y)^2 – 10x^2(4y)^3 + 5x(4y)^4 – (4y)^5\).
Question
▶️ Answer/Explanation
The general term of the expansion $(a + b)^n$ is given by $T_{k+1} = \binom{n}{k} a^{n-k} b^k$.
For $p(x) = (x – 3)^5$, we have $n = 5$, $a = x$, and $b = -3$.
To find the $x^3$ term, we set the exponent of $x$ to $3$, so $n – k = 3$.
Solving for $k$ gives $5 – k = 3$, which means $k = 2$.
The term is $\binom{5}{2} (x)^3 (-3)^2$.
The binomial coefficient $\binom{5}{2} = \frac{5 \cdot 4}{2 \cdot 1} = 10$.
The coefficient of the $x^3$ term is therefore $10 \cdot (-3)^2$.
This matches option (B).
Question
▶️ Answer/Explanation
The correct answer is (D).
The binomial theorem states $(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k}b^k$.
For $(x + 3y)^5$, the power $n = 5$, so the expansion has $n+1 = 6$ terms.
The coefficients are found using the 5th row of Pascal’s Triangle: $1, 5, 10, 10, 5, 1$.
The powers of $x$ decrease from $5$ to $0$, while powers of $(3y)$ increase from $0$ to $5$.
Applying these coefficients yields $1x^5 + 5x^4(3y)^1 + 10x^3(3y)^2 + 10x^2(3y)^3 + 5x^1(3y)^4 + 1(3y)^5$.
This matches the expression provided in option (D).
Question
▶️ Answer/Explanation
(C) \( x^4 + 8x^3 + 24x^2 + 32x + 16 \)
Using the Binomial Theorem, \[ (a+b)^4 = a^4 + 4a^3b + 6a^2b^2 + 4ab^3 + b^4 \] Substituting \( a = x \) and \( b = 2 \): \[ (x+2)^4 = x^4 + 4x^3(2) + 6x^2(2^2) + 4x(2^3) + 2^4 \] \[ = x^4 + 8x^3 + 24x^2 + 32x + 16 \] Thus, the correct answer is (C).
1. Apply the binomial formula: \( (a+b)^4 = a^4 + 4a^3b + 6a^2b^2 + 4ab^3 + b^4 \).
2. Substitute \( a = x \), \( b = 2 \).
3. Compute each term: \( 4x^3(2) = 8x^3 \).
4. Compute \( 6x^2(2^2) = 6x^2(4) = 24x^2 \).
5. Compute \( 4x(2^3) = 4x(8) = 32x \).
6. Compute \( 2^4 = 16 \).
7. Combine all terms: \( x^4 + 8x^3 + 24x^2 + 32x + 16 \).
8. Therefore, the equivalent expression is option (C).
Question
▶️ Answer/Explanation
2. Compute each term: \( 4(3)=12 \), \( 6(9)=54 \), \( 4(27)=108 \), \( 3^4=81 \).
3. Therefore, \( (x+3)^4 = x^4 + 12x^3 + 54x^2 + 108x + 81 \).
4. Comparing with \( x^4 + ax^3 + bx^2 + cx + d \):
5. \( a=12 \), \( b=54 \), \( c=108 \), \( d=81 \).
6. The greatest value among \( 12, 54, 108, 81 \) is \( 108 \).
7. Hence, the greatest coefficient is \( c \).
Question
▶️ Answer/Explanation
1. By the Remainder Theorem, compute \( f(-3) \).
\( f(-3) = 2(-27) – 3(9) – 23(-3) + 12 = -54 – 27 + 69 + 12 = 0. \)
2. Since \( f(-3) = 0 \), the remainder is \(0\).
3. Perform synthetic division by \(-3\): the quotient is \( 2x^2 – 9x + 4 \).
4. Compute the discriminant:
\( \Delta = (-9)^2 – 4(2)(4) = 81 – 32 = 49. \)
5. Since \( \Delta = 49 > 0 \), the quadratic factors over the real numbers.
6. Factor: \( 2x^2 – 9x + 4 = (2x – 1)(x – 4). \)
Therefore, the remainder is \(0\) and the quotient factors into real linear factors.
Question
▶️ Answer/Explanation
(D)
1. Divide \(6x^4\) by \(3x^2\) to get \(2x^2\); subtract to obtain \(9x^3\).
2. Divide \(9x^3\) by \(3x^2\) to get \(3x\); subtract to obtain \(6x^2\).
3. Divide \(6x^2\) by \(3x^2\) to get \(2\); subtract to obtain remainder \(7x – 5\).
4. Since the remainder is \(7x – 5 \neq 0\), \(g(x)\) is not a factor of \(f(x)\).
5. Degree of \(f(x)\) is \(4\); degree of \(g(x)\) is \(2\).
6. The degree difference is \(2\), so the quotient is quadratic (not linear).
7. A slant asymptote occurs only when the degree difference is \(1\).
8. Therefore, the correct statement is (D).
Question
Directions:
- Unless otherwise specified, the domain of a function \( f \) is assumed to be the set of all real numbers \( x \) for which \( f(x) \) is a real number. Angle measures for trigonometric functions are assumed to be in radians.
- Solutions to equations must be real numbers. Determine the exact value of any expression that can be obtained without a calculator.
- Unless otherwise specified, combine terms using algebraic methods and rules for exponents and logarithms where applicable.
- For each part of the question, show the work that leads to your answers.
(A) The functions \( g \) and \( h \) are given by
\( g(x) = 3^{(2x)} \cdot 3^{(x+4)} \)
\( h(x) = 2\tan^2 x – 1 \)
(ii) Solve \( h(x) = 5 \) for values of \( x \) in the interval \( [0, 2\pi) \).
(B) The functions \( j \) and \( k \) are given by
\( j(x) = 2\log_{10}(x+3) – \log_{10} x – \log_{10} 3 \)
\( k(x) = \frac{(\tan^2 x)(\cot x)}{\csc x} \)
(ii) Rewrite \( k(x) \) as a fraction involving \( \sec x \) and no other trigonometric functions.
(C) The function \( m \) is given by
\( m(x) = \frac{2^{(5x+3)}}{\left(2^{(x-2)}\right)^3} \)
▶️ Answer/Explanation
(A)(i) Solve \( g(x) = 27 \)
First, simplify the expression for \( g(x) \) using the property of exponents \( a^m \cdot a^n = a^{m+n} \).
\( g(x) = 3^{2x} \cdot 3^{x+4} = 3^{(2x + x + 4)} = 3^{(3x+4)} \)
Set \( g(x) \) equal to 27 and rewrite 27 as a base of 3:
\( 3^{(3x+4)} = 27 \)
\( 3^{(3x+4)} = 3^3 \)
Since the bases are equal, the exponents must be equal:
\( 3x + 4 = 3 \)
\( 3x = 3 – 4 \)
\( 3x = -1 \)
\( x = -\frac{1}{3} \)
(A)(ii) Solve \( h(x) = 5 \) on \( [0, 2\pi) \)
Set the expression for \( h(x) \) equal to 5:
\( 2\tan^2 x – 1 = 5 \)
Add 1 to both sides:
\( 2\tan^2 x = 6 \)
Divide by 2:
\( \tan^2 x = 3 \)
Take the square root of both sides:
\( \tan x = \pm\sqrt{3} \)
The reference angle for \( \tan \theta = \sqrt{3} \) is \( \frac{\pi}{3} \).
Since we have \( \pm\sqrt{3} \), we must consider solutions in all four quadrants within the interval \( [0, 2\pi) \):
Quadrant I: \( x = \frac{\pi}{3} \)
Quadrant II: \( x = \pi – \frac{\pi}{3} = \frac{2\pi}{3} \)
Quadrant III: \( x = \pi + \frac{\pi}{3} = \frac{4\pi}{3} \)
Quadrant IV: \( x = 2\pi – \frac{\pi}{3} = \frac{5\pi}{3} \)
Solution set: \( x = \frac{\pi}{3}, \frac{2\pi}{3}, \frac{4\pi}{3}, \frac{5\pi}{3} \)
(B)(i) Rewrite \( j(x) \) as a single logarithm
Given: \( j(x) = 2\log_{10}(x+3) – \log_{10} x – \log_{10} 3 \)
Use the power rule \( n\log a = \log(a^n) \):
\( = \log_{10}((x+3)^2) – \log_{10} x – \log_{10} 3 \)
Factor out the negative sign for the last two terms to group them:
\( = \log_{10}((x+3)^2) – (\log_{10} x + \log_{10} 3) \)
Use the product rule \( \log a + \log b = \log(ab) \):
\( = \log_{10}((x+3)^2) – \log_{10}(3x) \)
Use the quotient rule \( \log a – \log b = \log(\frac{a}{b}) \):
\( = \log_{10}\left(\frac{(x+3)^2}{3x}\right) \)
(B)(ii) Rewrite \( k(x) \) involving \( \sec x \)
Given: \( k(x) = \frac{(\tan^2 x)(\cot x)}{\csc x} \)
First, simplify the numerator using \( \tan x \cdot \cot x = 1 \):
\( (\tan^2 x)(\cot x) = \tan x \cdot (\tan x \cdot \cot x) = \tan x \cdot 1 = \tan x \)
Now substitute back into the expression:
\( k(x) = \frac{\tan x}{\csc x} \)
Convert to sine and cosine:
\( = \frac{\frac{\sin x}{\cos x}}{\frac{1}{\sin x}} \)
\( = \frac{\sin x}{\cos x} \cdot \frac{\sin x}{1} = \frac{\sin^2 x}{\cos x} \)
We need the expression in terms of \( \sec x \). Use the identity \( \sin^2 x = 1 – \cos^2 x \):
\( = \frac{1 – \cos^2 x}{\cos x} \)
Substitute \( \cos x = \frac{1}{\sec x} \):
\( = \frac{1 – \left(\frac{1}{\sec x}\right)^2}{\frac{1}{\sec x}} \)
\( = \frac{1 – \frac{1}{\sec^2 x}}{\frac{1}{\sec x}} \)
Find a common denominator for the numerator:
\( = \frac{\frac{\sec^2 x – 1}{\sec^2 x}}{\frac{1}{\sec x}} \)
Multiply by the reciprocal of the denominator:
\( = \frac{\sec^2 x – 1}{\sec^2 x} \cdot \frac{\sec x}{1} \)
\( = \frac{\sec^2 x – 1}{\sec x} \)
(C) Find input values for \( m(x) = \frac{1}{16} \)
First, simplify the expression for \( m(x) \):
\( m(x) = \frac{2^{(5x+3)}}{\left(2^{(x-2)}\right)^3} \)
Simplify the denominator using the power rule \( (a^m)^n = a^{m \cdot n} \):
\( \left(2^{(x-2)}\right)^3 = 2^{3(x-2)} = 2^{3x-6} \)
Now apply the quotient rule \( \frac{a^m}{a^n} = a^{m-n} \):
\( m(x) = \frac{2^{5x+3}}{2^{3x-6}} = 2^{(5x+3) – (3x-6)} \)
\( = 2^{5x + 3 – 3x + 6} \)
\( = 2^{2x + 9} \)
Set \( m(x) = \frac{1}{16} \) and rewrite \( \frac{1}{16} \) as a power of 2:
\( \frac{1}{16} = \frac{1}{2^4} = 2^{-4} \)
Equate the simplified \( m(x) \) to \( 2^{-4} \):
\( 2^{2x + 9} = 2^{-4} \)
Equate the exponents:
\( 2x + 9 = -4 \)
\( 2x = -13 \)
\( x = -\frac{13}{2} \) or \( -6.5 \)
