Answer: π/3.
- A π/3
- B π/6
- C π/4
- D π/2
Correct answer: A. π/3
Explanation: cos(π/3) = 1/2, so cos⁻¹(1/2) = π/3.
The graph of sin⁻¹x is confined to a narrow domain [-1,1] (since sine itself only takes values in that range) and range [-π/2,π/2] (the principal value branch chosen to make sine one-one and invertible there).
Concept context
Restricting trig functions to make them invertible, the principal value branches of sin-inverse, cos-inverse, tan-inverse, and friends, and the key identities relating them.