Answer: pi/6.
- A pi/6
- B pi/4
- C pi/3
- D pi/2
Correct answer: A. pi/6
Explanation: sin(pi/6) = 1/2, and pi/6 lies within the principal range, so sin-1(1/2) = pi/6.
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.