- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Without using trigonometric tables, find the value of the following expression:
$\frac{sec( 90^{o}-\theta ) .cosec\theta -tan( 90^{o} -\theta ) cot\theta +cos^{2} 25^{o}+cos^{2} 65^{o} }{3tan27^{o} tan63^{o}}$.
Given:
$\frac{sec( 90^{o} -\theta ) .cosec\theta -tan( 90^{o} -\theta ) cot\theta +cos^{2} 25^{o} +cos^{2} 65^{o} }{3tan27^{o} tan63^{o}}$
To do: To find the value of the given expression without using trigonometric tables.
Solution: The given experession :
$\frac{sec( 90^{o} -\theta ) .cosec\theta -tan( 90^{o} -\theta ) cot\theta +cos^{2} 25^{o} +cos^{2} 65^{o} }{3tan27^{o} tan63^{o}}$
$\because sec( 90^{o} -\theta ) =cosec\theta ,\ sin( 90^{o} -\theta ) =cos\theta ,\ tan( 90^{o} -\theta ) =cot\theta $
$=\frac{cosec\theta .cosec\theta -cot\theta .cot\theta +sin^{2}( 90^{o}-25^{o} ) +cos^{2} 65^{o} }{3cot( 90^{o} -27^{o} ) .tan63^{o} }$
$=\frac{cosec^{2} \theta -cot^{2} \theta +sin^{2} 65^{o}+cos^{2} 65^{o} }{3cot63^{o} tan63^{o} }$
$=\frac{1+1}{3\times 1} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \left( \because cosec^{2} \theta -cot^{2} \theta =1,\ sin^{2} \theta +cos^{2} \theta =1\ and\ cot\theta .tan\theta =1\right)$
$=\frac{2}{3}$
The value of the given expression is $\frac{2}{3}$.
Advertisements