Question

    (cos5°+sin5°)/(cos5°-sin5°) is equal

    to:
    A tan5° Correct Answer Incorrect Answer
    B cot5° Correct Answer Incorrect Answer
    C tan50° Correct Answer Incorrect Answer
    D tan40° Correct Answer Incorrect Answer

    Solution

    (cos5°+sin5°)/(cos5°-sin5°) Divide the numerator and denominator by cos5° = (1+tan5°)/(1-tan5°) = (tan⁡ 45° + tan5°)/(1-tan45° ×tan⁡ 5° ){As tan (A + B) = (tanA°+tanB°)/(1-tanA°+tanB°) } = tan (45 + 5) = tan 50°

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