Question #048a8

1 Answer
Nov 19, 2017

1

Explanation:

sin(a)=(6565)

Get the arcsine

A=sin1(6565)

A=7.125o

But angle A is on quadrant III

Get coterminal angle

3607.125=352.875

Get reference angle

360352.875=7.125

Get angle on Quadrant III

180+7.125=187.125

Test A if derived angle is correct

sin(7.125)=0.124
sin(187.125)=0.124

Use angle A for half angle identity of cosine

cos(A2)=1+cos(187.125)2

Resulting to

=0.9981