Practicing Success
Practicing Success
CUET Preparation Today
If sin θ + sin2 θ = 1, then find cos8 θ + 2cos6 θ + cos4 θ - 3 is equal to: |
- 2 - 5 2 - 6 |
- 2 |
⇒ sin θ + sin2 θ = 1 ⇒ sin θ = 1 - sin2 θ = cos2 θ ⇒ sin θ = cos2 θ and also sin2 θ = cos4 θ Now, ⇒ cos8 θ + 2cos6 θ + cos4 θ - 3 = (cos4 θ + cos2 θ)2 - 3 = (sin2 Θ + sin Θ)2 - 3 = (1)2 - 3 = -2 |
