How do I solve sin 2x=-1/2sin2x=−12 for 0<=x<=2pi0≤x≤2π?
1 Answer
Dec 2, 2017
Explanation:
sin2x=-1/2sin2x=−12
"since "sin2x<0" then x in third/fourth quadrants"since sin2x<0 then x in third/fourth quadrants
rArr2x=pi/6larrcolor(blue)"related acute angle"⇒2x=π6←related acute angle
"note "rarr0<=2x<=4pinote →0≤2x≤4π
2x=(7pi)/6,(11pi)/6,(19pi)/6,(31pi)/62x=7π6,11π6,19π6,31π6
rArrx=(7pi)/12" or "(11pi)/12" or "(19pi)/12" or "(31pi)/12⇒x=7π12 or 11π12 or 19π12 or 31π12