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Without using trigonometric tables, evaluate the following:

sec 17°cosec 73°+tan 68°cot 22°\dfrac{\text{sec 17°}}{\text{\text{cosec 73°}}} + \dfrac{\text{tan 68°}}{\text{cot 22°}} + cos2 44° + cos2 46°.

Trigonometrical Ratios

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Answer

Solving,

sec 17°cosec (90° - 17°)+tan (90° - 22°)cot 22°+cos244°+cos2(90°44°)sec 17°sec 17°+cot 22°cot 22°+cos244°+sin244°1+1+13.\Rightarrow \dfrac{\text{sec 17°}}{\text{cosec (90° - 17°)}} + \dfrac{\text{tan (90° - 22°)}}{\text{cot 22°}} + \text{cos}^2 44° + \text{cos}^2 (90° - 44°) \\[1em] \Rightarrow \dfrac{\text{sec 17°}}{\text{sec 17°}} + \dfrac{\text{cot 22°}}{\text{cot 22°}} + \text{cos}^2 44° + \text{sin}^2 44° \\[1em] \Rightarrow 1 + 1 + 1 \\[1em] \Rightarrow 3.

Hence, sec 17°cosec 73°+tan 68°cot 22°\dfrac{\text{sec 17°}}{\text{\text{cosec 73°}}} + \dfrac{\text{tan 68°}}{\text{cot 22°}} + cos2 44° + cos2 46° = 3.

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