Question
tan 20˚ x tan 23˚ x tan 67˚ x tan 70˚ =
?Solution
We know that If tanA x tanB = 1 then A & B are complementary angles it means A + B = 90˚ Here 20˚ + 70˚ = 90˚ & 23˚ + 67˚ = 90˚ So tan 20˚ x tan 70˚ = 1 & tan 23˚ x tan 67˚ = 1 Hence tan 20˚ x tan 23˚ x tan 67˚ x tan 70˚ = 1
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