Question

Consider all angles whose reference angle is 45° with terminal sides not in Quadrant I.The angles that share the same cosine value as cos 45° have terminal sides in quadrant

Answer 1

Solution:

As we know reference angle is smallest angle between terminal side and X axis.

As cosine 45 ° is always positive in first and fourth quadrant.

i.e CosФ, Cos (-Ф) or Cos(2π - Ф) have same value.

As, Cos 45°, Cos (-45°) or Cos ( 360° - 45°)= Cos 315°are same.

So, Angles that share the same Cosine value as Cos 45° have same terminal sides  will be in Quadrant IV having value Either Cos (-45°) or Cos (315°).

Also, Cos 45° = Sin 45° or Sin 135° i.e terminal side in first Quadrant or second Quadrant.

Answer 2

Actually, i just took the assignment.
answers are:
1. cosine - IV
2. sine - II
3. tangent - III