Ineed with this problem if someone could be of assistance

1) cos 105°

2) tan 67.5°

3) sin 67.5°

4) tan 165°

Step-by-step explanation:

From half angle identity

For sin 67.5 = sin (135/2)

Here 67.5° lies in Ist quadrant therefore

For cos 105 = cos (210/2)

From half angle identity

Since cos 105 lies in second quadrant

Therefore

For tan165 = tan (330/2)

From half angle identity

For tan 67.5 = tan (135/2)

From half angle identity