Unit 2 of 5
Study guide for CLEP CLEP Calculus — Unit 2: Derivatives. Practice questions, key concepts, and exam tips.
76
Practice Questions
17
Flashcards
11
Key Topics
Try these 5 questions from this unit. Sign up for full access to all 76.
If f(x) = , what is the derivative of f(x) with respect to x?
9x
6x
6
Answer: D — The derivative of f(x) with respect to x is found using the power rule, which states that if f(x) = $x^{n}$, then f'(x) = $nx^{n-1}$. Applying this rule to f(x) = $3x^{2}$ yields f'(x) = $3 \cdot 2x^{2-1}$ = $6x$.
If f(x) = , what is the average rate of change of f(x) over the interval [1, 3]?
0
3
6
12
15
Answer: D — The average rate of change is calculated as (f(3) - f(1)) / (3 - 1) = (27 - 3) / 2 = 12.
A state's education budget is modeled by the function C(x) = + 5x + 1, where C(x) is the number of graduates and x is the public investment in education in millions of dollars. What is the instantaneous rate of change of graduates with respect to the investment when x = 4?
2 + 5(4)
18
2(4) + 5
21
19
Answer: D — The derivative of C(x) is C'(x) = 4x + 5. Evaluating at x = 4, C'(4) = 4(4) + 5 = 21.
If f(x) = , find f'(x) using the quotient rule.
f'(x) = (2 - (2x + 1)(2)) / ( - 4)^2
f'(x) = (2 - (2x + 1)(2x)) / ( - 4)^2
f'(x) = (2( - 4) + (2x + 1)(2x)) / ( - 4)^2
f'(x) = (2( - 4) - (2x + 1)(2x)) / ( - 4)^2
f'(x) = (2( - 4) + (2x + 1)(2x)) / ( - 4)
Answer: D — The quotient rule states that if f(x) = g(x)/h(x), then f'(x) = (h(x)g'(x) - g(x)h'(x)) / (h(x))^2, so f'(x) = (2(x^2 - 4) - (2x + 1)(2x)) / (x^2 - 4)^2 is correct because it applies this rule with g(x) = 2x + 1, h(x) = x^2 - 4, g'(x) = 2, and h'(x) = 2x.
If f(x) = , what is the instantaneous rate of change of f at x = 2?
lim (h → 0) [f(2 + h) - f(2)]/h = 12
lim (h → 0) [f(2 + h) - f(2)]/h = 6
lim (h → 0) [f(2 + h) - f(2)] = 12
lim (h → 0) [f(2 + h) - f(2)]/h = 0
lim (h → 0) [f(2 + h) - f(2)]/h = -12
Answer: A — To find the instantaneous rate of change, we use the limit definition of a derivative. For f(x) = $3x^{2}$, f'(x) = lim (h → 0) [f(x + h) - f(x)]/h. At x = 2, f'(2) = lim (h → 0) [3(2 + h)^2 - 3(2)^2]/h = lim (h → 0) [3(4 + 4h + $h^{2}$) - 12]/h = lim (h → 0) [12 + 12h + $3h^{2}$ - 12]/h = lim (h → 0) [12h + $3h^{2}$]/h = lim (h → 0) [12 + 3h] = 12.
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