cos tetha = -1/2, tetha = ? Share with your friends Share 0 Sandeep Saurav answered this Dear Student, Given : cos θ=-12To Calculate : the value of θSolution : As we know in (-π, π)if cos θ=-12then,⇒θ=±2π3 And in (π, 3π)if cos θ=-12then,⇒θ=4π3, 8π3So, the general Solution can be written forcos θ=-12⇒ θ=(2n+1)π±π3 , where n∈ℤ Hope this information will clear your doubts about topic. If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible. Keep posting!! Regards 0 View Full Answer