English, asked by gkatiyar538, 10 months ago

If 3 tan2 0 - 1 = 0, find cos 20, given that 0 is acute.

Answers

Answered by nikithajain0105
5

Answer:

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Explanation:

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Answered by Anonymous
11

Solution :-

Let theta = A

3tan²A - 1 = 0

3tan²A = 1

tan²A = 1/3

tan A = (1/3)

tan A = 1/3

tan A = tan 30

A = 30

Now,

Cos 2A = Cos ( 2 × 30) = Cos 60 = 1/2

Cos²A = Cos ² 30 = (3/2)² = 3/4

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