Question #ffd93

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Answer 1 · 2017-11-15T03:53:55

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#sin (5x) cos (7x) — cos (5x) sin (7x) =-0.55#

#sin(5x-7x)=-0.55#—>#sin (A-B)=sinAcosB-cosAsinB#

#sin(-2x)=-0.55#

#-sin(2x)=-0.55#—>#sin(-x)=-sin x#

#sin(2x)=0.55#

#2x=sin^-1 0.55#

#2x=0.5823642379+2pin or 2x=2.559228416 +2pin#

#x=0.2911821189+pin or x=1.279614208+pin#—>divide by 2

#n=0, x=0.29, 1.28#

#S={0.29}#