If (x-y) x and (x+y) are in HP, then x 5 e c(y / 2) is equal to
Mathematics · JEE Main · NTA Exams — Progression and Series
If \(\cos (x-y) \cos x \text { and } \cos (x+y)\) are in HP, then \(\cos x \cdot 5 e c(y / 2)\) is equal to
- \(\pm \sqrt{2}\)
- \(\pm 1 \sqrt{2}\)
- 2
- None of these
Answer
(A) 2
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