What is the exact value of cos112.5?

The exact value of cos⁡ 112.5 is

Solution:

Use half angle formula for Cos,

(Since cos 112.5 is in II quadrant ,negative sign is used)            

cos⁡  225 = cos⁡ (45+180)

cos ⁡(a+b) = cos a cos b+sin a sin⁡ b

cos ⁡(45+180) = cos 45 cos⁡ 180+ sin⁡ 45 sin ⁡180

cos⁡ 180 = -1  

sin⁡ 180 = 0

apply equation 2 in equation 1

7

step-by-step explanation:

yuo ned the activity or vertical angle of the form of 1,7 but 2,2 has a c4,2 as it verticie so i not have a car