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Standard Values of Trigonometric Ratios

The angle of ...

Question

The angle of elevation of the top and bottom of a flag staff fixed at the top of a tower at a point distance $a f t$ . from the foot of a tower are $α$ and $β$ . Prove that the height of the flag staff is
$a (tan α - tan β)$ .

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Solution

$A C = a tan α, A B = a tan β$
$∴ B C = A C - A B = a (tan α - tan β)$

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