Trigonometry
±1−cos2x1+cos2x\pm\frac{\sqrt{1-\cos^2x}}{1+\cos^2x}
±1−cos2x1−cos2x\pm\frac{\sqrt{1-\cos^2x}}{1-\cos^2x}
±1+cos2x1−cos2x\pm\frac{\sqrt{1+\cos^2x}}{1-\cos^2x}
±1+cos2x1+cos2x\pm\frac{\sqrt{1+\cos^2x}}{1+cos^2x}