मराठी

Prove that: cos A (1 + cot A) + sin A (1 + tan A) = sec A + cosec A - Mathematics

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प्रश्न

Prove that:

cos A (1 + cot A) + sin A (1 + tan A) = sec A + cosec A

बेरीज

उत्तर

L.H.S. = cos A (1 + cot A) + sin A (1 + tan A)

= `cosA(1 + cosA/sinA) + sinA(1 + sinA/cosA)`

= `(cosA(sinA + cosA))/sinA + (sinA(cosA + sinA))/cosA`

= `(sinA + cosA)[cosA/sinA + sinA/cosA]`

= `(sinA + cosA)[(cos^2A + sin^2A)/(sinAcosA)]`

= `(sinA + cosA) xx 1/(sinAcosA)`

= `(sinA + cosA)/(sinAcosA)`  ...[∵ cos2θ + sin2θ = 1]

= `sinA/(sinAcosA) + cosA/(sinAcosA)`

= `1/cosA + 1/sinA`

= sec A + cosec A = R.H.S.

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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 10.04 | पृष्ठ ३३३
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