# Shared Flashcard Set

## Details

Pre-Calculus - Identities
Sum, Difference, Double Angle, Power-Reducing & Half Angle Identities
15
Mathematics
11/26/2012

Term
 SUM IDENTITY   sin(u+v)   mix it up
Definition
 SUM IDENTITY   sinu cosv + cosu sinv
Term
 SUM IDENTITY   cos(u+v)   Creep Cousins Keep it together
Definition
 SUM IDENTITY   cosu cosv + sinu sinv
Term
 SUM IDENTITY   tan(u+v)
Definition
 SUM IDENTITY   tanu + tanv 1 - tanu tanv
Term
 DIFFERENCE IDENTITY   sin(u-v)
Definition
 DIFFERENCE IDENTITY   sinu cosv - cosu sinv
Term
 DIFFERENCE IDENTITY   cos(u-v)    Creep Cousins Keep it together
Definition
 DIFFERENCE IDENTITY   cosu cosv + sinu sinv
Term
 DIFFERENCE IDENTITY   tan(u-v)
Definition
 DIFFERENCE IDENTITY   tanu - tanv 1 + tanu tanv
Term
 DOUBLE ANGLE IDENTITY   sin(2u)
Definition
 DOUBLE ANGLE IDENTITY   2 sinu cosv
Term
 DOUBLE ANGLE IDENTITY   cos(2u)   (3 forms)
Definition
 DOUBLE ANGLE IDENTITY   1:  cos2u - sin2u   2:  1 - 2sin2u  3:  2cos2u - 1
Term
 DOUBLE ANGLE IDENTITY   tan(2u)
Definition
 DOUBLE ANGLE IDENTITY   2tanu 1 - tan2u
Term
 HALF ANGLE IDENTITY   sin(θ/2)
Definition
 HALF ANGLE IDENTITY   ±√[(1 - cosθ)/2]
Term
 HALF ANGLE IDENTITY   cos(θ/2)
Definition
 HALF ANGLE IDENTITY   ±√[(1 + cosθ)/2]
Term
 HALF ANGLE IDENTITY   tan(θ/2)
Definition
 HALF ANGLE IDENTITY   ±√[(1 - cosθ)/(1 + cosθ)]   = (1 - cosθ)/sinθ   = sinθ/(1 + cosθ)
Term
 POWER REDUCING IDENTITY   sin2u
Definition
 POWER REDUCING IDENTITY   1 - cos(2u) 2   or   ½ - ½cos(2u)
Term
 POWER REDUCING IDENTITY   cos2u
Definition
 POWER REDUCING IDENTITY    1 + cos(2u) 2   or   ½ + ½cos(2u)
Term
 POWER REDUCING IDENTITY   tan2u
Definition
 POWER REDUCING IDENTITY   sin2u cos2u   =   1 - cos(2u) 1 + cos(2u)
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