is  the sum of  the areas   of  two triangles:  .(C) Because     is  a   semicircle  of  radius  8,  its area    is  32π.    The
domain   is  [−8,8],     or  16  units   wide.   Hence   the     average     height  of  the
function    is  .(C) The average value   is  equal   to  .(C) The average value   is  equal   to  .(C)  From    the     integral,   we  get    a    =   1,  b   =   5,  so  and    .   Replace x   with    xk  and replace dx  with    Δx  in  the
integrand   to  get the general term    in  the summation.
(D)  From    the     integral,   we  get    a    =   0, b    =   π,  so  and    .   Replace x   with    xk  and replace dx  with    Δx  in  the
integrand   to  get the general term    in  the summation.
(B) From    the Riemann Sum,    we  see  ,  then     .  Notice  that
the term    involving   k   in  the Riemann Sum is  not equal   to   but    .
Thus,   we  choose   ,  so  a   =   0   and  ,  so  b   =   3.  Since   xk
replaces    x,  f(x)    =   sin(2x  +   2)  giving  the integral    .