# Express function as a trigonometric function of x

(@harikasmiley)
New Member
Joined: 2 years ago
Posts: 1
13/05/2019 10:08 am
sin(4x)sin⁡(4x)

use sin2a=2sinacosasin⁡2a=2sin⁡acos⁡a then

sin4x=2sin2xcos2xsin⁡4x=2sin⁡2xcos⁡2x

with cos(2x)=cos2(x)sin2(x)cos⁡(2x)=cos2⁡(x)−sin2⁡(x) replace again

sin4x=4sinxcosx+cos2(x)sin2(x)

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