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Introduction to Trigonometry
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13/06/2021 11:32 am
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Evaluate :
(i) \(\frac{sin 18°}{cos 72°}\)
(ii) \(\frac{tan 26°}{cot 64° }\)
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13/06/2021 11:35 am
(i) \(\frac{sin \;18°}{cos \; 72°}\)
We know that, 18° is written as 90° – 18°, which is equal to the cos 72°.
= sin (90° – 18°) /cos 72°
Substitute the value, to simplify this equation
= \(\frac{sin \;72°}{cos \; 72°}\) = 1
(ii) \(\frac{tan\; 26°}{cot\; 64° }\)
We know that, 26° is written as 90° – 36°, which is equal to the cot 64°.
= tan (90° – 36°)/cot 64°
Substitute the value, to simplify this equation
= \(\frac{tan\; 64°}{cot\; 64° }\) = 1