Question 206780
cos{ (3pi/4) +x} +sin { (3pi/4) -x}
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The  ref  angle  for  (3pi/4) = pi/4
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cos { (3pi/4 +x} = -cos (pi/4 -x),,,as  long  as  x<pi/4
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sin { (3pi/4)-x} = sin (pi/4 +x)
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-cos (pi/4-x) + sin(pi/4 +x)
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sin(pi/4 +x) - cos(pi/4-x)
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 Discussion: it  is  tempting  to  use  the  "sum  and  difference  identities"
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but  this  does  not  appear  to  "simplify"
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Realizing  that  (pi/4) is  45  degrees,  this  is  not  a  bad  simplification