Trig Identities are needed in some problems 

to manipulate expressions before derivative or integrals 

can be taken and to simplify answers.  

You MUST know the Basic Identities.

 IDENTITIES  Howe-Two (Advanced )

You can practice these in the lab

Pythagorean and sum-Difference--used

Identities II to practice sum/difference

 

sin (a ± b) = sin a cosb  ±  cosa sinb

cos (a ± b) = cos a cosb   sina sinb

        tan ((a ± b)=

sin(2a)=2 sin a cos a

cos (2a) = cos2 a -  sin2 a

cos (2a) = 2cos2 a -  1

cos (2a) = 1 - 2 sin2 a

 

 You also need to know odd-even identities and phase shift.sin(x)= - sun(-x)   cos(x)=cos(-x)   cos (x-p/2) = sin (x)   cos(x +p/2) = -sin(x)

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