The value of tan 11° tan 17° tan 79° tan 73° is

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The value of tan 11° tan 17° tan 79° tan 73° is

1. 1
  2
2. 0
3. 1
4. 1
  √2

Correct Option: C

tan 11°.tan 17°.tan 79°.tan 73°
= tan 11°.tan 17°.tan (90° – 11°). tan (90° – 17°)
= tan 11°.tan 17°.cot 11°.cot 17°
= tan 11°.cot11°.tan17°.cot 17°
= 1 × 1 = 1 [∵ tan (90° – θ)
= cotθ; tanθ . cotθ = 1]

	1
	√2