Math Calculator

Half Angle Formula

Half angle formulas are used to integrate the rational trigonometric expressions. It can be derived from the double angle identities and can be used to find the half angle identity of sine, cosine, tangent. Enter the angle into the calculator and click the function for which the half angle should be calculated, your answer will be displayed.

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Formula Used:

sin( θ / 2 ) = √ 1 - cosθ / 2 cos( θ / 2 ) = √ 1 + cosθ / 2 tan( θ / 2 ) = 1 - cosθ / sinθ

Example:

For a 50 Degree angle, the half angle identity of trigonometric function for sin, cos and tan values is

sin θ/2 = √1 - cosθ / 2

= √1 - cos(50) / 2
= √1 - 0.64278760968 / 2
= 0.42262
= 0.42262

cos θ/2 = √1 + cosθ / 2

= √1 + cos(50) / 2
= √1 + 0.64278760968 / 2
= 0.90631
= 0.90631

tan θ/2 = 1 - cosθ / sinθ

= 1 - cos(50) / sin(50)
= 1 - 0.64278760968 / 0.76604444311
= 0.46631
= 0.46631