मराठी

Prove that `Cot^2a-cot^2b=(Cos^2a-cos^2b)/(Sin^2asin^2b)=Cosec^2a-cosec^2b` - Mathematics

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प्रश्न

Prove that

`cot^2A-cot^2B=(cos^2A-cos^2B)/(sin^2Asin^2B)=cosec^2A-cosec^2B`

उत्तर

`cot^2A-cot^2B`

`=cos^2A/sin^2A-cos^2B/sin^2B`

`=(cos^2Asin^2B-cos^2Bsin^2A)/(sin^2Asin^2B)`

`=(cos^2A(1-cos^2B)-cos^2B(1-cos^2A))/(sin^2Asin^2B)`

`=(cos^2A-cos^2Acos^2B-cos^2B+cos^2Bcos^2A)/(sin^2Asin^2B)`

`=(cos^2A-cos^2B)/(sin^2Asin^2B)`

`=(1-sin^2A-1+sin^2B)/(sin^2Asin^2B)`

`=(-sin^2A+sin^2B)/(sin^2Asin^2B)`

`=sin^2B/(sin^2AsinB)-sin^2A/(sin^2Asin^2B)`

`=1/sin^2A-1/sin^2B`

= cosec2A - cosec2B

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पाठ 21: Trigonometrical Identities - Exercise 21 (E) [पृष्ठ ३३३]

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सेलिना Mathematics [English] Class 10 ICSE
पाठ 21 Trigonometrical Identities
Exercise 21 (E) | Q 10.09 | पृष्ठ ३३३
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