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Prove that cot x cot 2x – cot 2x cot 3x – cot 3x cot x = 1 - Mathematics

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प्रश्न

Prove the following:

cot x cot 2x – cot 2x cot 3x – cot 3x cot x = 1

योग

उत्तर

cot 3x = cot(2x + x) = `(cot 2x  cot x-1)/(cot x + cot 2x)`  `[∵ cot (A + B) = (cot A cot B - 1)/(cot A + cot B)]`

⇒ cot 3x (cot x + cot 2x) = cot 2x cot x - 1

⇒ cot 3x cot x + cot 3x cot 2x = cot 2x cot x - 1

⇒ cot x cot 2x - cot 2x cot 3x - cot 3x cot x = 1

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अध्याय 3: Trigonometric Functions - Exercise 3.3 [पृष्ठ ७४]

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एनसीईआरटी Mathematics [English] Class 11
अध्याय 3 Trigonometric Functions
Exercise 3.3 | Q 22 | पृष्ठ ७४

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