I was sick alot last week so i really am still grasping the lessons of the past week
the formulas i solve and use well are the
Sum and Difference formulas for Cosine and Sine:
cos (alpha + or - beta) = cos(alpha)cos(beta) - or + sin(alpha)sin(beta)
sin (alpha + or - beta) = sin(alpha)cos(beta) + or - cos(alpha)sin(beta)
and
Rewriting a Sum or Difference as a Product:
sin(x) + sin(y) = 2sin(x+y/2)cos(x-y/2)
sin(x) - sin(y) = 2cos(x+y/2)sin(x-y/2)
cos(x) + cos(y) = 2cos(x+y/2)
cos(x-y/2)cos(x) - cos(y) = -2sin(x+y/2)sin(x-y/2)
the one type of problem that i really need help with are the ones that say solve for an equation when equal to _<_<_
if someone could please please explain how to work problem like this and possibly give an example that would be so great.
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okay so basically when you see that all its doing is giving you more information to narrow down the question to work the problem. Usually a problem will have that to tell you which quadrant the number is in or where on the unit circle it is. If it contains like 90 degrees and pi, then you know its in the second quadrant.
ReplyDeleteI hope this help! Its kinda hard to explain on a comment.