मराठी
महाराष्ट्र राज्य शिक्षण मंडळएस.एस.सी (इंग्रजी माध्यम) इयत्ता १० वी

Prove that sec^2A – cosec^2A = (2sin^2A – 1)/(sin^2A*cos^2A).

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प्रश्न

Prove that `sec^2A - "cosec"^2A = (2sin^2A - 1)/(sin^2A *cos^2A)`.

सिद्धांत
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उत्तर

L.H.S. = sec2A – cosec2A

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

= `(sin^2A - cos^2A)/(cos^2A*sin^2A)`

= `(sin^2A - (1 - sin^2A))/(sin^2A*cos^2A)`   ...`[(∵ sin^2A + cos^2A = 1),(∴ 1 - sin^2A = cos^2A)]`

= `(sin^2A - 1 + sin^2A)/(sin^2A*cos^2A)`

= `(2sin^2"A" - 1)/(sin^2"A"*cos^2"A")`

= R.H.S.

∴ `sec^2A - "cosec"^2A = (2sin^2A - 1)/(sin^2A*cos^2A)`

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पाठ 6: Trigonometry - Exercise

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