If \( \tan \mathrm{A}=5 / 4 \), it means.... a. \( \quad \cos 2 \mathrm{~A}=-9 / 41 \) b. \( \cos 2 \mathrm{~A}=9 / 41 \) c. \( \cos 2 \mathrm{~A}=-41 / 9 \) d. \( \cos 2 \mathrm{~A}=41 / 9 \)
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Let's consider a right-angled triangle where the opposite side (O) is 5 units and the adjacent side (A) is 4 units. Show more…
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