हिंदी

If (tan θ + sin θ) = m and (tan θ – sin θ) = n, prove that (m^2 – n^2)^2 = 16 mn.

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प्रश्न

If (tan θ + sin θ) = m and (tan θ – sin θ) = n, prove that (m2 – n2)2 = 16 mn.

प्रमेय
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उत्तर

We have `(tan theta + sin theta ) = m and ( tan theta - sin theta )=n`

 Now,LHS = `(m^2-n^2)^2`

                 =`[(tan^2 theta + sin theta )^2 - "( tan theta - sin theta )^2]^2`

                =`[(tan^2 theta + sin^2 theta + 2 tan  theta  sin theta )-( tan^2 theta + sin^2 theta -2 tan theta sin theta )]^2`

               =`[(tan^2 theta +sin^2 theta + 2 tan theta sin theta - tan^2 theta -  sin^2 theta+ 2 tan theta sin theta )]^2`

              =`(4 tan theta sin theta )^2`

              =`16 tan^2 theta sin^2 theta`

              =`16 (sin ^2 theta )/(cos^2 theta ) sin^2 theta`

              =`16 ((1- cos^2 theta) sin ^2 theta)/ cos^2 theta`

               =` 16 [ tan^2 theta (1- cos^2 theta)]`

               =`16 (tan^2 theta - tan^2 theta cos^2 theta)`

               =`16 (tan^2 theta -(sin^2 theta)/(cos^2 theta) xx cos^2 theta )s`

              =`16 ( tan^2 theta - sin^2 theta )`

              =`16 (tan theta + sin theta ) ( tan theta - sin theta)`

              =`16 mn                 [(tan theta + sin^theta )( tan theta - sin theta ) =mn]`

               =`∴ (m^2 - n^2 )(m^2 - n^2 )^2 = 16 mn`          

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अध्याय 13: Trigonometric identities - EXERCISE 13В [पृष्ठ ६२८]

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आर.एस. अग्रवाल Mathematics [English] Class 10
अध्याय 13 Trigonometric identities
EXERCISE 13В | Q 6. | पृष्ठ ६२८

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