All questions
Question 1
Two quadratic functions p(x)=ax2+bx+c and q(x)=dx2+ex+f satisfy the following: p(1)=3, p(3)=7, p(5)=15, and q(1)=8, q(3)=2, q(5)=4. Over the interval [1,5], which statement is most accurate?
- Function p has a consistently increasing rate of change while q has a consistently decreasing rate
- Function q has a greater average rate of change than p over this interval despite local variations
- Both functions have the same average rate of change, but their instantaneous rates differ significantly
- Function p has a greater average rate of change than q, with p accelerating and q decelerating (correct answer)
Explanation: For p(x): average rate over [1,5] = (15-3)/(5-1) = 3. The differences are: p(3)-p(1) = 4, p(5)-p(3) = 8, showing increasing rate (acceleration). For q(x): average rate over [1,5] = (4-8)/(5-1) = -1. The differences are: q(3)-q(1) = -6, q(5)-q(3) = 2, showing the rate is becoming less negative (deceleration in the negative direction). Since 3 > -1, function p has greater average rate of change. Function p shows acceleration (increasing positive rate), while q shows deceleration (rate changing from negative to positive). Choice A is wrong about q having consistently decreasing rate. Choice B is wrong because p has greater average rate. Choice C is wrong because average rates differ (3 vs -1).
Question 2
Two quadratic functions u(x)=−x2+6x−5 and v(x)=2x2−8x+11 are compared on the interval [1,4]. Which function has the greater average rate of change, and why?
- Function u because it increases on this entire interval while v decreases
- Function v because its rate of change is 2 compared to u's rate of 1 (correct answer)
- Function u because both functions have the same rate of change
- Function v because it has a larger leading coefficient magnitude
Explanation: Calculate the average rates of change on [1,4]. For u(x): u(1) = -1 + 6 - 5 = 0, u(4) = -16 + 24 - 5 = 3. Average rate = (3-0)/(4-1) = 1. For v(x): v(1) = 2 - 8 + 11 = 5, v(4) = 32 - 32 + 11 = 11. Average rate = (11-5)/(4-1) = 2. Since 2 > 1, function v has the greater average rate of change.
Question 3
Consider the quadratic functions F(x)=−2x2+16x−30 and G(x)=x2−6x+13. On the interval [3,6], which function has the greater average rate of change?
- Function F because it has a larger coefficient for the x term
- Function G because its average rate of change is 3 (correct answer)
- Function F because its average rate of change is −6
- Function G because it increases while F decreases on this interval
Explanation: Calculate average rates on [3,6]. For F(x): F(3) = -18 + 48 - 30 = 0, F(6) = -72 + 96 - 30 = -6. Average rate = (-6-0)/(6-3) = -2. For G(x): G(3) = 9 - 18 + 13 = 4, G(6) = 36 - 36 + 13 = 13. Average rate = (13-4)/(6-3) = 3. Since 3 > -2, function G has the greater average rate of change. F decreases on this interval (vertex at x = 4), while G increases throughout (vertex at x = 3).
Question 4
Function p(x)=ax2+bx+c passes through points (−1,8), (0,3), and (2,7). Function q(x)=2x2−x+1. On the interval [1,3], which function grows faster?
- Function p grows faster because it has a y-intercept of 3
- Function q grows faster because its leading coefficient is positive
- Function p grows faster because its average rate of change is 4
- Function q grows faster because its average rate of change is 7 (correct answer)
Explanation: First, find p(x) using the three points. From (0,3): c = 3. Using (-1,8) and (2,7): a - b + 3 = 8 and 4a + 2b + 3 = 7, giving a - b = 5 and 4a + 2b = 4, so 2a + b = 2. Solving: a = 1, b = 0. Thus p(x) = x² + 3. On [1,3]: p(1) = 4, p(3) = 12, average rate = (12-4)/(3-1) = 4. For q(x): q(1) = 2(1) - 1 + 1 = 2, q(3) = 2(9) - 3 + 1 = 16, average rate = (16-2)/(3-1) = 7. Since 7 > 4, function q grows faster.
Question 5
Function m(x)=0.5x2+3x−1 and function n(x) has the property that n(0)=5, n(2)=1, and n(4)=5. Over the interval [0,4], which statement about their growth patterns is correct?
- Function m grows faster because it has a positive leading coefficient
- Function n grows faster because its average rate of change is zero
- Function m grows faster because its total change is 20 units (correct answer)
- Function n grows faster because it decreases then increases symmetrically
Explanation: For m(x): m(0) = -1, m(4) = 0.5(16) + 3(4) - 1 = 8 + 12 - 1 = 19. Total change = 19 - (-1) = 20 units. For n(x): n(0) = 5, n(4) = 5. Total change = 0 units. Average rate for m: 20/4 = 5. Average rate for n: 0/4 = 0. Function m grows faster with a positive average rate of change compared to n's zero average rate.
Question 6
Function r(x)=x2−2x+4 and function s(x)=−0.5x2+4x−3 are analyzed on the interval [0,2]. Based on their average rates of change, which conclusion is most accurate?
- Function r grows faster with an average rate of change of 0
- Function s grows faster with an average rate of change of 3 (correct answer)
- Function r grows faster because it has positive leading coefficient
- Function s grows faster because its vertex is within the interval
Explanation: Calculate average rates on [0,2]. For r(x): r(0) = 4, r(2) = 4 - 4 + 4 = 4. Average rate = (4-4)/(2-0) = 0. For s(x): s(0) = -3, s(2) = -0.5(4) + 4(2) - 3 = -2 + 8 - 3 = 3. Average rate = (3-(-3))/(2-0) = 3. Since 3 > 0, function s grows faster with an average rate of change of 3.
Question 7
Consider the quadratic functions h(x)=2x2−8x+11 and j(x)=−x2+6x−4. Over the interval [2,4], which statement about their comparative behavior is most accurate?
- Both functions are increasing, with h increasing faster due to its larger leading coefficient magnitude
- Function h is increasing while j is decreasing, making direct rate comparison challenging but meaningful (correct answer)
- Function j is increasing while h is decreasing, with j having the greater rate of positive change
- Both functions are decreasing, with j decreasing faster due to its negative leading coefficient
Explanation: For h(x): vertex at x = 2, so h is increasing for x > 2. Over [2,4]: h(2) = 8-16+11 = 3, h(4) = 32-32+11 = 11, so h increases by 8. For j(x): vertex at x = 3, so j increases for x < 3 and decreases for x > 3. j(2) = -4+12-4 = 4, j(3) = -9+18-4 = 5, j(4) = -16+24-4 = 4. So j increases from 2 to 3, then decreases from 3 to 4, with net change = 0. Since h is consistently increasing while j increases then decreases over [2,4], choice B correctly identifies this behavior. The comparison is meaningful because we can compare average rates (8/2 = 4 for h vs 0/2 = 0 for j). Choice A is wrong because j isn't consistently increasing. Choice C has the directions reversed. Choice D is wrong because h isn't decreasing.
Question 8
Two quadratic functions f(x)=2x2−4x+1 and g(x)=−x2+4x−1 are analyzed over the interval [0,3]. Which statement best characterizes how their growth patterns compare?
- Both functions start increasing, but f accelerates upward while g reaches maximum then decelerates downward
- Function f decreases then accelerates upward, while g increases then gradually decreases to negative values
- Function g increases then decreases symmetrically, while f decreases then increases with greater final slope (correct answer)
- Both functions exhibit similar initial behavior but diverge significantly in their rates during the latter portion
Explanation: For f(x): vertex at x = 1, f'(x) = 4x - 4. f decreases for x < 1, increases for x > 1. f(0) = 1, f(1) = -1, f(3) = 7. For g(x): vertex at x = 2, g'(x) = -2x + 4. g increases for x < 2, decreases for x > 2. g(0) = -1, g(2) = 3, g(3) = 2. Over [0,3]: f decreases then increases (1 to -1 to 7), while g increases then decreases (-1 to 3 to 2). Function g's behavior is more symmetric around its vertex at x = 2. Function f has steeper final slope: f'(3) = 8, while g'(3) = -2. Choice C correctly describes both behaviors and notes f's greater final slope magnitude.
Question 9
Function A(x)=3x2−12x+15 and function B(x)=−x2+8x−12 are compared on interval [2,5]. Which function exhibits faster growth over this interval?
- Function A because its average rate of change is 9 (correct answer)
- Function B because its average rate of change is −1
- Function A because it increases throughout the interval
- Function B because its vertex creates optimal growth conditions
Explanation: Calculate average rates on [2,5]. For A(x): A(2) = 12 - 24 + 15 = 3, A(5) = 75 - 60 + 15 = 30. Average rate = (30-3)/(5-2) = 9. For B(x): B(2) = -4 + 16 - 12 = 0, B(5) = -25 + 40 - 12 = 3. Average rate = (3-0)/(5-2) = 1. Function A grows much faster with rate 9 vs B's rate of 1. The vertex of A is at x = 2 and it increases from there. The vertex of B is at x = 4, so B increases then decreases on [2,5].
Question 10
Two quadratic functions are given: h(x)=x2−4x+7 and k(x)=3(x−1)2+2. Over which interval does function k have a greater average rate of change than function h?
- [0,1] because k has a larger leading coefficient
- [1,3] because k increases more rapidly away from its vertex (correct answer)
- [2,4] because both functions are increasing but k has steeper growth
- [−1,1] because h is decreasing while k remains relatively constant
Explanation: First, find the vertices: h(x) has vertex at x = 2, k(x) has vertex at x = 1. For [1,3]: h(1) = 4, h(3) = 4, so average rate = 0. k(1) = 2, k(3) = 14, so average rate = 6. For [0,1]: h(0) = 7, h(1) = 4, rate = -3. k(0) = 5, k(1) = 2, rate = -3. For [2,4]: h(2) = 3, h(4) = 7, rate = 2. k(2) = 5, k(4) = 29, rate = 12. For [-1,1]: h(-1) = 12, h(1) = 4, rate = -4. k(-1) = 14, k(1) = 2, rate = -6. Only on [1,3] does k have a greater (more positive) average rate of change.