Trigonometry
Identify the equation which has a solution equal to 2π3\frac{2\pi}{3}32π .
x=cos−1(−12)x=\cos^{-1}\left(-\frac12\right)x=cos−1(−21)
x=cos−1(−22)x=\cos^{-1}\left(-\frac{\sqrt2}{2}\right)x=cos−1(−22)
x=tan−1(−1)x=\tan^{-1}\left(-1\right)x=tan−1(−1)
x=sin−1(22)x=\sin^{-1}\left(\frac{\sqrt2}{2}\right)x=sin−1(22)