How do you find the value for sin(arccos(13))?

2 Answers
Jun 11, 2015

Use calculator to evaluate θ=arccos(13), allow for θ+π (since cos(θ)=cos(θ+π)); use calculator to evaluate the two values of theta (within the 0 to 2π range.

Explanation:

Using caluclator
XXXXarccos(13)=1.910633
XXXXXXXXi.e cos(1.910633)=13
XXXXnote that
XXXXXXXXcos(1.910633+π) also =13

Using calculator evaluate:
XXXXsin(1.910633)=0.942809
and
XXXXsin(1.910633+π)=sin(4.372552)=0.942809

Jun 11, 2015

Findsin(arccos(13))

Explanation:

cosx=13--> arc x?

Calculator gives x=±109.47.
Now, find sin(±109.47)

sin (109.47) = 0.94
sin (-109.47) = -0.94