Cracking The Ap Calculus ab Exam 2018

(Marvins-Underground-K-12) #1

  1. If we take the limit as x goes to 0, we get an indeterminate form , so let’s use L’Hôpital’s


Rule.    We  take    the     derivative  of  the     numerator   and     the     denominator     and     we  get    

=    .   Now,    when    we  take    the     limit   we  get    

.



  1. If  we  take    the limit   as  x   goes    to  0,  we  get an  indeterminate   form     ,  so  let’s   use L’Hôpital’s



Rule.    We  take    the     derivative  of  the     numerator   and     the     denominator     and     we  get    

=    =   .   Let’s   use

some    trig    identities  to  simplify    the numerator   and denominator.    We  know    that    1   −   cos^2 θ =   sin^2

θ   and sec^2 θ −   1   =   tan^2 θ.    We  get     =       =   .

Next,   substitute      for tan^2   θ:      =    .  Now,    when    we

take    the limit   we  get  2cos^2 θ   =   2.

SOLUTIONS TO PRACTICE PROBLEM SET 18


1.

Here     we  will    use     the     Power   Rule,   which   says    that    .   The     integral    is 

= + C.

2. 10 + C

Here     we  will    use     the     Power   Rule,   which   says    that    .   The     integral    is 

= = .
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