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  1. If 7sin²θ + 3cos²θ = 4, and 0° < θ < 90°, then the value of tanθ is :
    1. 1
      2
    2. 1
      3
    3. 3
      2
    4. 1
Correct Option: B

7 sin²θ + 3 cos²θ = 4
On dividing by cos²θ,

7 sin²θ
+
3 cos²θ
=
4
cos²θcos²θcos²θ

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

⇒ tan²θ =
1
3



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