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Question
Evaluate tan 35° tan 40° tan 50° tan 55°
Solution
tan 35° = tan (90° - 55°) = cot 55°
tan 40° = tan (90° - 50°) = cot 55°
tan 65° = 1
cot 55 tan 55∙ cot 50 tan 50 ∙ tan 45
1 ∙ 1 ∙ 1 = 1
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