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Maharashtra State BoardSSC (English Medium) 10th Standard

(sec θ + tan θ) . (sec θ – tan θ) = ?

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Question

(sec θ + tan θ) . (sec θ – tan θ) = ?

Sum
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Solution

(sec θ + tan θ)(sec θ – tan θ)

= sec2θ – tan2θ   ...[∵ (a + b)(a – b) = a2 – b2]

= 1   ...`[(∵ 1 + tan^2θ = sec^2θ),(∴ sec^2θ - tan^2θ = 1)]`

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Chapter 6: Trigonometry - Q.1 (B)

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Activity:

L.H.S. = `square`

= `cos^2θ xx square`   ...`[1 + tan^2θ = square]`

= `(cos θ xx square)^2`

= 12

= 1

= R.H.S.


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= cosecθ × secθ

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