Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1
If  we  multiply    through by  8,  we  get 8y  +   8   =   9x  −   18  or  9x  −   8y  −   26  =   0.


  1. D Acceleration is the second derivative of position with respect to time (velocity is the first
    derivative).


The first   derivative  is  v(t)    =   3t^2    −   12t +   9.

The second  derivative  is  a(t)    =   6t  −   12.

Now we  simply  plug    in  t   =   4   and we  get a(4)    =   24  −   12  =   12.


  1. D The derivative of an expression of the form au, where u is a function of x, is


au  =   au  (ln a)  

Here    we  get

    3 πx    =   3πx (ln 3)π


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


that    the average value   of  f(x)    on  the interval    [a, b]  is   f(x)   dx.

Here    we  have    .

Evaluating  the integral,   we  get ln  x   =   ln  e   −   ln  1   =   1.  Therefore,  the answer  is  .


  1. C We just use the Chain Rule three times.


f′(x)   =   2   sin x   cos x   =   sin 2x

f′′(x)  =   2   cos 2x

f′′′(x) =   −4  sin 2x


  1. B First, we need to find using implicit differentiation.

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