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  1. If θ > 0, be an acute angle, then the value of θ in degrees stisfying cos 73° cos² 22° +
    1
    is :
    cot 17° sec² 68°
    1. 0
    2. 1
    3. 2
    4. 3
Correct Option: B

cot 17° . cot 73° . cos²22° +
cot 17°
cot 17°.sec² 68°

= cot 17° . cot (90° – 17°) . cos²22° + cos²68°
= cot 17° . tan 17° . cos²22° + cos²(90° – 22°)
= cos²22° + sin²22° = 1
[∵ cot (90° – θ) = tanθ ; cos (90° – θ) = sinθ]



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