Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1
graph   of  f′(x)   that    is  positive    from    x   =   2   to  x   =   ∞.  The graph   in  (D) satisfies   all of  these
requirements.


  1. C Remember that ln(u(x)) = .


We  will    need    to  use the Chain   Rule    to  find    the derivative.

f′(x)   =    (3)    =   −   3tan(3x)


  1. B The Second Fundamental Theorem of Calculus tells us how to find the derivative of an


integral.   It  says    that     f(t)   dt  =   f(u) ,  where   c   is  a   constant    and u   is  a   function    of  x.

Here    we  can use the theorem to  get     =   .

Now we  evaluate    the expression  at  x   =   −4. We  get     =   2.


  1. D Velocity is the first derivative of position with respect to time.


The first   derivative  is: v(t)    =   2t  −   7.

Thus,   the velocity    of  the particle    is  zero    at  time    t   =   3.5 seconds.


  1. A We can use u-substitution to evaluate the integral.


Let u   =   sin^2 x and du  =   2   sin x   cos x   dx. Next,   recall  from    trigonometry    that    2   sin x   cos x   =

sin(2x). Now we can substitute into the integral ∫eu du, leaving out the limits of integration for


the moment.

Evaluate the integral to get ∫eu du = eu.


Now,    we  substitute  back    to  get esin

(^2) x
.
Finally, we evaluate at the limits of integration to get



  1. B In order to find the average value, we use the Mean Value Theorem for Integrals, which says

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