Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1

. Now we can factor out the h from the numerator and cancel it with the h in


the denominator:    f′(x)   =       =    (2x    +   h   +   1). Now we

take    the limit   to  get f′(x)   =    (2x    +   h   +   1)  =   2x  +   1.


  1. 3 x^2 + 3


We  find    the derivative  of  a   function,   f′(x),  using   the definition  of  the derivative, which   is  f′(x)   =

. Here f(x) = x^3 + 3x + 2 and f(x + h) = (x + h)^3 + 3(x + h) + 2 = x^3 +


3 x^2 h +   3xh^2   +   h^3     +   3x  +   3h  +   2.

If  we  now plug    these   into    the definition  of  the derivative, we  get f′(x)   =   

= .

This    simplifies  to  f′(x)   =    .  Now we  can factor  out the h   from    the

numerator   and cancel  it  with    the h   in  the denominator:    f′(x)    =  

    =    (3x^2  +   3xh +   h^2     +   3). Now we  take    the limit   to  get f′(x)   =   

(3x^2   +   3xh +   h^2     +   3)  =   3x^2    +   3.

15.

We  find    the derivative  of  a   function,   f(x),   using   the definition  of  the derivative, which   is  f′(x)   =   

. Here f(x) = and f(x + h) = . If we now plug these into the


definition  of  the derivative, we  get f′(x)   =       =    .  Notice  that    if

we  now take    the limit,  we  get the indeterminate   form     .  We  cannot  eliminate   this    problem

merely   by  simplifying     the     expression  the     way     that    we  did     with    a   polynomial.     Here,   we

combine  the     two     terms   in  the     numerator   of  the     expression  to  get    f′(x)    =   =  
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