Practice Test 7 - AP Calculus AB

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. A runner's distance s(t)s(t) increases with speed proportional to s(t)\sqrt{s(t)}. Which differential equation models ss?
  2. Select the washer-method integral when the region between y=32x+2y=\tfrac{3}{2}x+2 and y=12x+1y=\tfrac{1}{2}x+1 on [0,4][0,4] is revolved about the x-axis.
  3. Let E(x)=∫−2xt2+1t2+4 dtE(x)=\int_{-2}^{x}\dfrac{t^2+1}{t^2+4}\,dt. What is E′(x)E'(x)?
  4. A function is B(x)=sin⁡x+cos⁡x+tan⁡xB(x)=\sin x+\cos x+\tan x. Which differentiation procedure is sufficient to find B′(x)B'(x)?
  5. Let k(x)={x2,x<24,x=25,x>2k(x)=\begin{cases}x^2,&x<2\\4,&x=2\\5,&x>2\end{cases}. Is kk continuous at x=2x=2, and why?
  6. What integral gives the volume if the base is bounded by x=0x=0 and x=9−y2x=\sqrt{9-y^2} for −3≤y≤3-3\le y\le 3, with semicircular cross sections perpendicular to the yy-axis?
  7. For f(x)=∣x∣xf(x)=\frac{|x|}{x} with f(0)f(0) undefined, does f′(0)f'(0) exist, and why?
  8. For s(x)={sin⁡x,x≠01,x=0s(x)=\begin{cases}\sin x,&x\ne0\\1,&x=0\end{cases}, is ss continuous at x=0x=0, and why?
  9. Define F(x)=∫0xg(t) dtF(x)=\int_{0}^{x} g(t)\,dt. If gg is positive on (0,2)(0,2) and negative on (2,4)(2,4), what must be true about FF at x=2x=2?
  10. An antiderivative of p(x)p(x) is P(x)=1x−x2P(x)=\frac{1}{x}-x^2. Evaluate ∫13p(x) dx\int_{1}^{3} p(x)\,dx using FTC.
  11. The derivative f′(x)f'(x) decreases on (−3,0)(-3,0) and increases on (0,5)(0,5). Where is ff concave up and down?
  12. A physics integral is ∫x2+8x+20x+4 dx\int \frac{x^2+8x+20}{x+4}\,dx. Which is an antiderivative?
  13. A function satisfies f′(x)=4−4xf'(x)=4-4x for 0≤x≤20\le x\le 2. What is f(2)−f(0)f(2)-f(0)?
  14. A bank account balance changes at −15-15 dollars/week due to fees; what does this mean?
  15. A rectangle with perimeter 6060 has length xx and width 30−x30-x; which xx maximizes area A=x(30−x)A=x(30-x)?
  16. Does y=x2+1y=x^2+1 satisfy dydx=2x\dfrac{dy}{dx}=2x at every xx?
  17. A particle's average velocity is (x+1)2−4x−1\dfrac{(x+1)^2-4}{x-1}; find lim⁡x→1(x+1)2−4x−1\lim\limits_{x\to 1}\dfrac{(x+1)^2-4}{x-1}.
  18. For 0<x<50<x<5, maximize f(x)=x(5−x)2f(x)=x(5-x)^2; which xx gives the maximum?
  19. A product's demand price is p(x)=50−2xp(x)=50-2x dollars; revenue is R(x)=xp(x)R(x)=xp(x) for 0<x<250<x<25. Which xx maximizes revenue?
  20. A differentiable one-to-one function pp satisfies p(0)=7p(0)=7 and p′(0)=5p'(0)=5; compute (p−1)′(7)(p^{-1})'(7).

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