Difficulty: Medium
Correct Answer: 24/7
Explanation:
Introduction / Context:
This question tests how to convert one trigonometric ratio into another for an acute angle. Given cosec θ, we can find sin θ. Then, because the angle is acute, all ratios are positive and we can use a right-triangle interpretation to compute cot θ = cos θ / sin θ.
Given Data / Assumptions:
Concept / Approach:
Use cosec θ = 1/sin θ, so sin θ = 7/25. Interpret sin θ = opposite/hypotenuse. That gives opposite = 7 and hypotenuse = 25 (scaled). Then use Pythagoras to find adjacent = sqrt(25^2 - 7^2) = 24. Finally, cot θ = adjacent/opposite = 24/7.
Step-by-Step Solution:
cosec θ = 25/7 => sin θ = 1/(25/7) = 7/25
Let opposite = 7 and hypotenuse = 25 for angle θ
Find adjacent using Pythagoras: adjacent^2 = 25^2 - 7^2 = 625 - 49 = 576
So adjacent = sqrt(576) = 24
cot θ = adjacent/opposite = 24/7
Verification / Alternative check:
cos θ would be adjacent/hypotenuse = 24/25. Then cot θ = cos θ / sin θ = (24/25)/(7/25) = 24/7, matching the result.
Why Other Options Are Wrong:
7/24 is tan θ, not cot θ (cot is the reciprocal).
24/25 is cos θ, not cot θ.
7/25 is sin θ, not cot θ.
25/24 is sec θ, not cot θ.
Common Pitfalls:
Confusing cot with tan, or inverting the ratio incorrectly. Another mistake is forgetting to use Pythagoras to find the missing side and assuming adjacent equals hypotenuse minus opposite, which is invalid.
Final Answer:
cot θ = 24/7
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