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Ex 8.3, 2 - Show that (i) tan 48 tan 23 tan 42 tan 67 = 1 - Ex 8.3

  1. Chapter 8 Class 10 Introduction to Trignometry
  2. Serial order wise
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Ex 8.3, 2 Show that : tan 48° tan 23° tan 42° tan 67 = 1 Taking L.H.S tan 48° tan 42° tan 23° tan 67° = tan 48° tan(90° – 48°) tan 23° tan(90° – 23°) = tan 48° cot 48° tan 23° cot 23° = (tan 48° × 1/tan⁡〖48°〗 ) × (tan 23° × 1/tan⁡〖23°〗 ) = 1 × 1 = 1 = R.H.S ∴ L.H.S = R.H.S Hence proved Ex 8.3, 2 Show that : (ii) cos 38° cos 52° – sin 38° sin 52° = 0 Taking L.H.S cos 38° cos 52° – sin 38° sin 52° = cos (90 – 52)° cos (90 – 38)° – sin 38° sin 52° = sin 52° sin 38° – sin 38° sin 52° = 0 = R.H.S ∴ L.H.S = R.H.S Hence proved

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