If 2cos2θ + 3sin θ = 3, where 0° < θ <90°, then what is the value of sin22θ + cos2θ + tan22θ + cosec22θ
If 2cos2θ + 3sin θ = 3, where 0° < θ <90°, then what is the value of sin22θ + cos2θ + tan22θ + cosec22θ Correct Answer 35/6
2cos2θ + 3sin θ = 3
⇒ 2(1 – sin2 θ) + 3 sin θ – 3 = 0
⇒ 2 – 2sin2 θ + 3 sin θ – 3 = 0
⇒ 2sin2 θ – 3 sin θ + 1 = 0
⇒ 2sin2 θ – 2sin θ - sin θ + 1 = 0
⇒ 2sin θ (sin θ – 1) – 1(sin θ - 1) = 0
⇒ (2sin θ – 1) (sin θ – 1) = 0
Taking,
⇒ sin θ – 1 = 0
⇒ sin θ = 1
⇒ sin θ = sin 90
⇒ θ = 90
Taking,
⇒ 2sin θ – 1 = 0
⇒ sin θ = 1/2
⇒ sin θ = sin 30
⇒ θ = 30
sin22θ + cos2θ + tan22θ + cosec22θ
⇒ sin260 + cos230 + tan260 + cosec260
⇒ (√3/2)2 + (√3/2)2 + (√3)2 + (2/√3)2
⇒ 35/6
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Feb 20, 2025