Prove that, if \(\tan\theta\tan(\theta+\alpha)=k\), then \[(k+1)\cos(2\theta+\alpha)=(1-k)\cos\alpha.\]
Solve the equation \[\tan\theta\tan(\theta+\pi/3)=2.\]
Discuss the equation \[\tan\theta\tan(\theta+\alpha)+1=0.\]
Prove that, if \(\tan\theta\tan(\theta+\alpha)=k\), then \[(k+1)\cos(2\theta+\alpha)=(1-k)\cos\alpha.\]
Solve the equation \[\tan\theta\tan(\theta+\pi/3)=2.\]
Discuss the equation \[\tan\theta\tan(\theta+\alpha)+1=0.\]