Applying Properties of Definite Integrals - AP Calculus AB

  1. Given ∫02p(x) dx=−4\int_{0}^{2} p(x)\,dx=-4 and ∫24p(x) dx=9\int_{2}^{4} p(x)\,dx=9, find ∫04p(x) dx\int_{0}^{4} p(x)\,dx.
    Answer: 55 This question assesses the skill of applying properties of definite integrals. Additivity sums the integrals from 0 to 2 and 2 to 4 into 0 to 4. That's -4 + 9 = 5. This merges the given values directly. A tempting distractor is -13, which subtracts instead of adding. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  2. If ∫29m(x) dx=−4\int_{2}^{9} m(x)\,dx=-4, what is ∫29(m(x)+5m(x)) dx\int_{2}^{9} \left(m(x)+5m(x)\right)\,dx?​
    Answer: −24-24 This problem requires applying the linearity property of definite integrals to combine like terms. Given ∫29m(x) dx=−4\int_{2}^{9} m(x)\,dx = -4, we need ∫29(m(x)+5m(x)) dx\int_{2}^{9} (m(x) + 5m(x))\,dx. First, simplify the integrand: m(x)+5m(x)=6m(x)m(x) + 5m(x) = 6m(x). Then use the constant multiple rule: ∫296m(x) dx=6∫29m(x) dx=6(−4)=−24\int_{2}^{9} 6m(x)\,dx = 6\int_{2}^{9} m(x)\,dx = 6(-4) = -24. A tempting mistake is to integrate each term separately as ∫m(x) dx+5∫m(x) dx=−4+5(−4)=−24\int m(x)\,dx + 5\int m(x)\,dx = -4 + 5(-4) = -24, which gives the correct answer but takes extra steps. Always simplify the integrand first, then apply integral properties for efficiency.
  3. Given ∫05h(x) dx=2\int_{0}^{5} h(x)\,dx=2 and ∫59h(x) dx=11\int_{5}^{9} h(x)\,dx=11, find ∫09h(x) dx\int_{0}^{9} h(x)\,dx.
    Answer: 1313 This problem requires applying the additivity property of definite integrals to combine adjacent intervals. Since the intervals [0,5][0,5] and [5,9][5,9] share the common endpoint 5, we can apply the additivity property: ∫09h(x) dx=∫05h(x) dx+∫59h(x) dx\int_{0}^{9} h(x)\,dx = \int_{0}^{5} h(x)\,dx + \int_{5}^{9} h(x)\,dx. Substituting the given values: ∫09h(x) dx=2+11=13\int_{0}^{9} h(x)\,dx = 2 + 11 = 13. The additivity property works because the upper limit of the first integral matches the lower limit of the second integral. A common mistake would be to subtract the values instead of adding them, yielding -9. Remember the properties checklist: additivity requires matching endpoints, direction matters for signs, and adjacent intervals combine by addition.
  4. If ∫−14g(x) dx=9\int_{-1}^{4} g(x)\,dx=9, what is ∫4−13g(x) dx\int_{4}^{-1} 3g(x)\,dx?
    Answer: −27-27 This problem requires applying properties of definite integrals to find the value without direct evaluation. We need to find ∫4−13g(x) dx\int_{4}^{-1} 3g(x)\,dx given that ∫−14g(x) dx=9\int_{-1}^{4} g(x)\,dx = 9. First, we apply the constant multiple property: ∫4−13g(x) dx=3∫4−1g(x) dx\int_{4}^{-1} 3g(x)\,dx = 3\int_{4}^{-1} g(x)\,dx. Next, we use the reversal property: ∫4−1g(x) dx=−∫−14g(x) dx=−9\int_{4}^{-1} g(x)\,dx = -\int_{-1}^{4} g(x)\,dx = -9. Therefore, ∫4−13g(x) dx=3(−9)=−27\int_{4}^{-1} 3g(x)\,dx = 3(-9) = -27. A tempting error is to multiply first without considering the reversed limits, which would give 27 (choice A). Remember the properties checklist: reversal changes sign, splitting uses addition, and constants factor out.
  5. Given ∫12h(x) dx=4\int_{1}^{2} h(x)\,dx=4 and ∫25h(x) dx=4\int_{2}^{5} h(x)\,dx=4, find ∫15h(x) dx\int_{1}^{5} h(x)\,dx.
    Answer: 88 This question assesses the skill of applying properties of definite integrals. The additivity property allows us to combine the integrals from 1 to 2 and 2 to 5 into the integral from 1 to 5. Both given integrals are 4, so their sum is 8. This direct addition determines the value efficiently. A tempting distractor is 16, which might come from mistakenly multiplying the values instead of adding. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  6. Given ∫04r(x) dx=1\int_{0}^{4} r(x)\,dx=1 and ∫410r(x) dx=7\int_{4}^{10} r(x)\,dx=7, what is ∫100r(x) dx\int_{10}^{0} r(x)\,dx?​
    Answer: −8-8 This problem combines the additive property and reversal property of definite integrals. We know ∫04r(x) dx=1\int_{0}^{4} r(x)\,dx = 1 and ∫410r(x) dx=7\int_{4}^{10} r(x)\,dx = 7, and need ∫100r(x) dx\int_{10}^{0} r(x)\,dx. First, find ∫010r(x) dx\int_{0}^{10} r(x)\,dx using additivity: ∫010r(x) dx=∫04r(x) dx+∫410r(x) dx=1+7=8\int_{0}^{10} r(x)\,dx = \int_{0}^{4} r(x)\,dx + \int_{4}^{10} r(x)\,dx = 1 + 7 = 8. Then apply the reversal property: ∫100r(x) dx=−∫010r(x) dx=−8\int_{10}^{0} r(x)\,dx = -\int_{0}^{10} r(x)\,dx = -8. A common error is reversing only one of the given integrals, yielding incorrect results like 6. Remember the checklist: additivity combines adjacent intervals, reversal changes sign, and work systematically.
  7. If ∫010p(x) dx=13\int_{0}^{10} p(x)\,dx=13, what is ∫010(p(x)−1) dx\int_{0}^{10} \left(p(x)-1\right)\,dx?
    Answer: 33 This question assesses the skill of applying properties of definite integrals. The linearity property lets us split the integral of p(x) - 1 into the integral of p(x) minus the integral of 1. The integral of 1 from 0 to 10 is 10, so 13 - 10 equals 3. This uses the constant integral rule alongside linearity. A tempting distractor is 23, which adds 10 instead of subtracting. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  8. If ∫27r(x) dx=9\int_{2}^{7} r(x)\,dx=9 and ∫24r(x) dx=1\int_{2}^{4} r(x)\,dx=1, what is ∫47r(x) dx\int_{4}^{7} r(x)\,dx?
    Answer: 88 This question assesses the skill of applying properties of definite integrals. The additivity property in reverse lets us find the integral from 4 to 7 by subtracting the integral from 2 to 4 from 2 to 7. Thus, 9 - 1 equals 8. This subtraction isolates the desired interval. A tempting distractor is 10, which adds 1 instead of subtracting. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  9. If ∫−11h(x) dx=4\int_{-1}^{1} h(x)\,dx=4, what is ∫−11(3h(x)+2) dx\int_{-1}^{1} \left(3h(x)+2\right)\,dx?
    Answer: 1616 This question assesses the skill of applying properties of definite integrals. Linearity splits the integral into 3 times the integral of h plus the integral of 2. That's 3*4 + 2*2 = 12 + 4 = 16. Constant integration uses the interval length of 2. A tempting distractor is 8, which forgets the constant term. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  10. If ∫14v(x) dx=3\int_{1}^{4} v(x)\,dx=3 and ∫49v(x) dx=12\int_{4}^{9} v(x)\,dx=12, find ∫91v(x) dx\int_{9}^{1} v(x)\,dx.
    Answer: −15-15 This problem tests your ability to apply both the additivity and reversal properties of definite integrals. First, find ∫19v(x) dx\int_{1}^{9} v(x)\,dx using additivity: ∫19v(x) dx=∫14v(x) dx+∫49v(x) dx=3+12=15\int_{1}^{9} v(x)\,dx = \int_{1}^{4} v(x)\,dx + \int_{4}^{9} v(x)\,dx = 3 + 12 = 15. Then apply the reversal property: ∫91v(x) dx=−∫19v(x) dx=−15\int_{9}^{1} v(x)\,dx = -\int_{1}^{9} v(x)\,dx = -15. The reversal of limits introduces a negative sign, changing our result from 15 to -15. A common error would be to simply add 3 and 12 without considering the reversed limits, yielding 15 instead of -15. Always remember the properties checklist: combine adjacent intervals first, then apply reversal to change sign, and the order of limits determines the final sign.
  11. If ∫03s(x) dx=2\int_{0}^{3} s(x)\,dx=2 and ∫39s(x) dx=5\int_{3}^{9} s(x)\,dx=5, find ∫09[s(x)−1] dx\int_{0}^{9} [s(x)-1] \,dx.
    Answer: −2-2 This problem requires applying properties of definite integrals to find the value without direct evaluation. We need to find ∫09[s(x)−1] dx\int_{0}^{9} [s(x)-1]\,dx given ∫03s(x) dx=2\int_{0}^{3} s(x)\,dx = 2 and ∫39s(x) dx=5\int_{3}^{9} s(x)\,dx = 5. First, we split the integral: ∫09[s(x)−1] dx=∫09s(x) dx−∫091 dx\int_{0}^{9} [s(x)-1]\,dx = \int_{0}^{9} s(x)\,dx - \int_{0}^{9} 1\,dx. Using the additive property: ∫09s(x) dx=∫03s(x) dx+∫39s(x) dx=2+5=7\int_{0}^{9} s(x)\,dx = \int_{0}^{3} s(x)\,dx + \int_{3}^{9} s(x)\,dx = 2 + 5 = 7. The integral of 1 over [0,9] is 9, so ∫09[s(x)−1] dx=7−9=−2\int_{0}^{9} [s(x)-1]\,dx = 7 - 9 = -2. A common error is forgetting to integrate the constant -1 over the entire interval, which would give 7 (choice A). Remember the properties checklist: reversal changes sign, splitting uses addition, and constants factor out.
  12. If ∫05p(x) dx=−7\int_{0}^{5} p(x)\,dx=-7, what is ∫05[p(x)+2] dx\int_{0}^{5} [p(x)+2] \,dx?
    Answer: 33 This problem requires applying properties of definite integrals to find the value without direct evaluation. We need to find ∫05[p(x)+2] dx\int_{0}^{5} [p(x)+2]\,dx given that ∫05p(x) dx=−7\int_{0}^{5} p(x)\,dx = -7. Using the linearity property, we can split the integral: ∫05[p(x)+2] dx=∫05p(x) dx+∫052 dx\int_{0}^{5} [p(x)+2]\,dx = \int_{0}^{5} p(x)\,dx + \int_{0}^{5} 2\,dx. The first integral equals -7, and the second integral equals 2(5−0)=102(5-0) = 10. Therefore, ∫05[p(x)+2] dx=−7+10=3\int_{0}^{5} [p(x)+2]\,dx = -7 + 10 = 3. A common error is to add 2 to the integral value instead of integrating the constant 2 over the interval, which would give -5 (choice C). Remember the properties checklist: reversal changes sign, splitting uses addition, and constants factor out.
  13. Given ∫−32r(x) dx=−6\int_{-3}^{2} r(x)\,dx=-6, what is ∫−32[−r(x)] dx\int_{-3}^{2} [-r(x)]\,dx?
    Answer: 66 This problem requires applying properties of definite integrals to find the value without direct evaluation. We need to find ∫−32[−r(x)] dx\int_{-3}^{2} [-r(x)]\,dx given that ∫−32r(x) dx=−6\int_{-3}^{2} r(x)\,dx = -6. Using the constant multiple property with c=−1c = -1: ∫−32[−r(x)] dx=−∫−32r(x) dx\int_{-3}^{2} [-r(x)]\,dx = -\int_{-3}^{2} r(x)\,dx. Since ∫−32r(x) dx=−6\int_{-3}^{2} r(x)\,dx = -6, we have ∫−32[−r(x)] dx=−(−6)=6\int_{-3}^{2} [-r(x)]\,dx = -(-6) = 6. A common mistake is thinking that negating the function doesn't change the integral value, leading to -6 (choice A). Remember the properties checklist: reversal changes sign, splitting uses addition, and constants factor out.
  14. If ∫−31k(x) dx=2\int_{-3}^{1} k(x)\,dx=2 and ∫16k(x) dx=−9\int_{1}^{6} k(x)\,dx=-9, find ∫−36k(x) dx\int_{-3}^{6} k(x)\,dx.​
    Answer: −7-7 This problem tests the additive property of definite integrals over adjacent intervals. Given ∫−31k(x) dx=2\int_{-3}^{1} k(x)\,dx = 2 and ∫16k(x) dx=−9\int_{1}^{6} k(x)\,dx = -9, we need ∫−36k(x) dx\int_{-3}^{6} k(x)\,dx. Since the intervals [-3,1] and [1,6] are adjacent at x=1, we can use additivity: ∫−36k(x) dx=∫−31k(x) dx+∫16k(x) dx=2+(−9)=−7\int_{-3}^{6} k(x)\,dx = \int_{-3}^{1} k(x)\,dx + \int_{1}^{6} k(x)\,dx = 2 + (-9) = -7. A tempting error is to subtract the integrals thinking of it as "from -3 to 1, then from 1 to 6," which would give 2 - (-9) = 11. Always remember: additivity means adding the integrals, regardless of their signs.
  15. Given ∫−14q(x) dx=−2\int_{-1}^{4} q(x)\,dx=-2, find ∫−14(−2q(x)) dx\int_{-1}^{4} \left(-2q(x)\right)\,dx.
    Answer: 44 This question assesses the skill of applying properties of definite integrals. The scalar multiple property allows us to factor out -2 from the integral, giving -2 times the given integral of -2. This results in -2 * -2 = 4. No further evaluation is needed due to this property. A tempting distractor is -4, which might occur by forgetting to apply the scalar to the given value correctly. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.
  16. Given ∫−12s(x) dx=−6\int_{-1}^{2} s(x)\,dx=-6, find ∫−12(2s(x)−3) dx\int_{-1}^{2} \big(2s(x)-3\big)\,dx.
    Answer: −21-21 This problem requires applying the linearity property of definite integrals to handle both a constant multiple and a constant term. Using linearity: ∫−12(2s(x)−3) dx=∫−122s(x) dx−∫−123 dx=2∫−12s(x) dx−3(2−(−1))\int_{-1}^{2} \big(2s(x)-3\big)\,dx = \int_{-1}^{2} 2s(x)\,dx - \int_{-1}^{2} 3\,dx = 2\int_{-1}^{2} s(x)\,dx - 3(2-(-1)). Substituting the given value: 2(−6)−3(3)=−12−9=−212(-6) - 3(3) = -12 - 9 = -21. The constant 3 integrates to 3 times the interval length, which is 3. A common mistake would be to write -3 instead of -9 for the constant term, forgetting to multiply by the interval length. Remember the properties checklist: linearity handles each term separately, constants factor out, and constant functions integrate to constant times interval length.
  17. If ∫28p(x) dx=−3\int_{2}^{8} p(x)\,dx=-3, what is ∫28(p(x)+5) dx\int_{2}^{8} \big(p(x)+5\big)\,dx?
    Answer: 2727 This problem tests your understanding of the linearity property of definite integrals, specifically how constants affect integration. We can split the integral using linearity: ∫28(p(x)+5) dx=∫28p(x) dx+∫285 dx\int_{2}^{8} \big(p(x)+5\big)\,dx = \int_{2}^{8} p(x)\,dx + \int_{2}^{8} 5\,dx. The first integral equals -3 (given), and the second integral of the constant 5 over the interval [2,8][2,8] equals 5(8−2)=305(8-2) = 30. Therefore, the answer is −3+30=27-3 + 30 = 27. A common error would be to simply add 5 to -3, giving 2, without recognizing that we're integrating the constant 5 over the entire interval. Always remember the properties checklist: linearity allows splitting sums, constants integrate to constant times interval length, and each term must be integrated separately.
  18. Given ∫−50u(x) dx=9\int_{-5}^{0} u(x)\,dx=9 and ∫02u(x) dx=−4\int_{0}^{2} u(x)\,dx=-4, find ∫−52u(x) dx\int_{-5}^{2} u(x)\,dx.
    Answer: 55 This problem requires applying the additivity property of definite integrals to combine two adjacent intervals. Since the intervals [−5,0][-5,0] and [0,2][0,2] share the common endpoint 0, we can use additivity: ∫−52u(x) dx=∫−50u(x) dx+∫02u(x) dx\int_{-5}^{2} u(x)\,dx = \int_{-5}^{0} u(x)\,dx + \int_{0}^{2} u(x)\,dx. Substituting the given values: ∫−52u(x) dx=9+(−4)=5\int_{-5}^{2} u(x)\,dx = 9 + (-4) = 5. The additivity property allows us to combine these integrals directly because they form a continuous interval from -5 to 2. A common mistake would be to subtract the integrals or change signs unnecessarily, perhaps getting −13-13 or 1313. Remember the properties checklist: additivity combines adjacent intervals by addition, signs are preserved as given, and endpoints must match for direct addition.
  19. If ∫−24g(x) dx=9\int_{-2}^{4} g(x)\,dx=9, what is ∫4−23g(x) dx\int_{4}^{-2} 3g(x)\,dx?​
    Answer: −27-27 This problem tests applying properties of definite integrals, particularly the constant multiple rule and reversal property. We start with ∫−24g(x) dx=9\int_{-2}^{4} g(x)\,dx = 9 and need ∫4−23g(x) dx\int_{4}^{-2} 3g(x)\,dx. By the reversal property, ∫4−23g(x) dx=−∫−243g(x) dx\int_{4}^{-2} 3g(x)\,dx = -\int_{-2}^{4} 3g(x)\,dx. Using the constant multiple rule, ∫−243g(x) dx=3∫−24g(x) dx=3(9)=27\int_{-2}^{4} 3g(x)\,dx = 3\int_{-2}^{4} g(x)\,dx = 3(9) = 27. Therefore, ∫4−23g(x) dx=−27\int_{4}^{-2} 3g(x)\,dx = -27. A tempting error is to multiply by 3 but forget the negative from reversing limits, giving 27. Always check: constants factor out, reversal changes sign, and order matters.
  20. If ∫59t(x) dx=0\int_{5}^{9} t(x)\,dx=0, what is ∫59(7t(x)) dx\int_{5}^{9} \left(7t(x)\right)\,dx?
    Answer: 00 This question assesses the skill of applying properties of definite integrals. The scalar multiple property factors out the 7, giving 7 times the integral of t(x), which is 7 * 0 = 0. This holds regardless of the function since the base integral is zero. No additional computation is required. A tempting distractor is 7, which ignores that the integral is zero. When working with definite integrals, remember this checklist: additivity over adjacent intervals, scalar multiples factor out, reversing limits adds a negative sign, and constants integrate to the constant times the interval length.

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