sin2x cos2x sinx o eBook 20 sin2x cosx 2 Solutioncos2t sin

sin2(x)- cos2(x) sin(x) o eBook 20. sin2(x)+ cos(x) 2

Solution

cos(2t)= - sin t

1-2sin²t =-sin t

2sin²t-sin t -1=0

2sin²t -2sin t + sin t -1=0

2sin t( sin t -1)+1(sin t -1)=0

(2sin t+1)(sin t -1)=0

sin t=-1/2, sin t=1

t= 7pi/6, 11pi/6, pi/2

t= pi/2, 7pi/6, 11pi/6