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The Value of (1 + Cot θ − Cosec θ) (1 + Tan θ + Sec θ) is

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Question

The value of (1 + cot θ − cosec θ) (1 + tan θ + sec θ) is 

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Solution

The given expression is 

`(1+cot θ-cosec θ )(1+tan θ+sec θ)`

Simplifying the given expression, we have 

`(1+cot θ-cosec θ)(1+tan θ+sec θ)` 

=`(1+cos θ/sin θ-1/sin θ)(1+sin θ/cos θ+1/cos θ)`

= `(sin θ+cos θ-1)/sin θxx (cos θ+sin θ+1)/cos θ` 

= `((sin θ+cos θ-1)(cos θ+sin θ+1))/(sin θcos θ)` 

=`({(sin θ+cos θ)-1}{(sin θ+cos θ)+1})/(sin θ cos θ)`

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

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

=`((sin^2 θ+cos^2θ+2 sin θcos θ)-1)/(sin θ cos θ)` 

=`((sin ^2θ+cos^2θ)+2 sinθ cos θ-1)/(sin θcos θ)` 

= `(1+2 sin θ cosθ-1)/(sinθ cos θ)` 

=`( 2 sin θ cos θ)/(sin θ cos θ)` 

=`2`

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Chapter 11: Trigonometric Identities - Exercise 11.4 [Page 57]

APPEARS IN

R.D. Sharma Mathematics [English] Class 10
Chapter 11 Trigonometric Identities
Exercise 11.4 | Q 9 | Page 57

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