How do you prove sin1(12)=π6?

1 Answer
Oct 2, 2016

See the Explanation.

Explanation:

The Defn. of sin1 fun. is :

sin1x=θ,|x|1sinθ=x,θ[π2,π2].

So, we have to find a θ, which satisfies the conds., namely,

(1):π2θπ2, & (2):sinθ=12.

Knowing that, sin(π6)=sin(π6)=12, and, noting

that, π6[π2,π2], we have,

sin1(12)=π6.