If sec²θ tan²θ=7, then sec4θ

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If sec²θ tan²θ= 7 , then sec⁴θ - tan⁴θ =
12

1. 7
  12
2. 1
  2
3. 5
  12
4. 1

Correct Option: A

sec⊃ θ – tan⊃ θ = 1

sec⊃ θ + tan⊃ θ =	7
	12

∴ sec⁴θ – tan⁴θ
= (sec⊃ θ – tan⊃ θ) (sec⊃ θ + tan⊃ θ)

= 1 ×		7	=	7
		12		12