If we now replace A by 12 A and take the square root we get. It is sometimes useful to define t as the tan of a half angle. Summary of Tan of a Half Angle tan alpha21-cos alphasin alphasin alpha1cos alpha Using t.
1 t2 4 1 t2 4 1 t.
If the angle lies in first or 4th. The half angle formula for Tangent is helpful when you need to determine the exa. The half angle formula for Sine is helpful when you need to determine the exact val. We will check the first one.