what is the value of sin(1/2 cos -1 4/5) Share with your friends Share 0 Ajanta Trivedi answered this the given trigonometric expression is sin12cos-145 let θ=12cos-145⇒2θ=cos-145 cos2θ=451-2sin2θ=452sin2θ=1-45=15sin2θ=110sinθ=±110 hope this helps you. 6 View Full Answer