Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1
We   find    the     derivative  using   the     Quotient    Rule,   which   says    that    if f(x)     =   ,   then   f′(x)    =  

. Here, f(x) = , so u = (x + 4)(x − 8) and v = (x + 6)(x − 6). Before we


take    the derivative, we  can simplify    the numerator   and denominator of  the expression: f(x)    =   

=    .   Now     using   the     Quotient    Rule,   we  get     f(x)    =  

. Next, we don’t simplify. We simply plug in x = 2 to get f(x) =


= = .

11. 106

We   find    the     derivative  using   the     Quotient    Rule,   which   says    that    if f(x)     =   ,   then   f′(x)    =  

. We will also need the Chain Rule to take the derivative of the expression in the


denominator.    The Chain   Rule    says    that    if  y   =   f(g(x)),    then    y′  =    ,  here,   f(x)    =   

,    so  u   =   x^6 +   4x^3 +  6   and     v   =   (x^4 -  2)^2 .  We  get     f(x)    =  

. Now we don’t simplify.


We  simply  plug    in  x   =   1   to  get

f(x)    =       =   

12.

We   find    the     derivative  using   the     Quotient    Rule,   which   says    that    if f(x)     =   ,   then   f′(x)    =  

. Here, f(x) = , so u = x^2 − 3 and v = x − 3. Using the Quotient Rule, we get f′


(x) =    .  This    can be  simplified  to  f′(x)   =   .

13. 6
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