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  1. If 7sin²θ + 3cos²θ = 4, then the value of tan θ is (θ is acute)
    1. 1
      3
    2. 1
      2
    3. 3
    4. 1
Correct Option: A

7
sin²θ
+
3cos²θ
=
4
cos²θcos²θcos²θ

⇒ 7 tan²θ + 3 = 4 sec²θ
⇒ 7 tan²θ + 3 = 4 (1 + tan²θ)
⇒ 7 tan²θ + 3 = 4 + 4 tan²θ
⇒ 7 tan²θ – 4 tan²θ = 4 – 3
⇒ 4 tan²θ = 1 ⇒ tan²θ =
1
3

⇒ tanθ =
1
3



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