What is the sin1(32)?

2 Answers
Sep 7, 2015

sin1(32)=π3 (radians)

Explanation:

sin1(32)=θ
XXmeans
sin(θ)=32
XXXXwith the restriction that θ[π2,π2]

The possible triangles with this ratio of y to hypotenuse (i.e. sin) are pictured below:
enter image source here
...but note that only π3 falls within the restricted range for sin1

May 10, 2016

θ = 60° or 120°

Explanation:

It helps if one recognises the lengths 3 and 2 as
being two of the sides in one of the special triangle,
namely 30°, 60° 90°.

Sketch this by drawing an equilateral triangle of sides 2 units, and drawing in a line of symmetry to form two right-angled triangles.

The hypotenuse is of length 2 units and the opposite side
is of length 3. The angle is therefore 60°.

However, the sign is positive. Sin is positive in the first and second quadrants.

Therefore θ = 60° or 120°