logo

Ask Questions, Get Answers

 
X
 Search
Want to ask us a question? Click here
Browse Questions
Ad
Home  >>  JEEMAIN and AIPMT  >>  Mathematics  >>  Trignometry
0 votes

The expression $\tan^2\alpha+\cot^2\alpha$ is

$(a)\;\geq 2\qquad(b)\;\leq 2\qquad(c)\;\geq -2\qquad(d)\;None\;of\;these$

Can you answer this question?
 
 

1 Answer

0 votes
$(\tan\alpha-\cot\alpha)^2\geq 0$
$\Rightarrow \tan^2\alpha+\cot^2\alpha-2\tan\alpha\cot\alpha\geq 0$
$\Rightarrow \tan^2\alpha+\cot^2\alpha-2\geq 0$
$\Rightarrow \tan^2\alpha+\cot^2\alpha\geq 2$
Hence (a) is the correct answer.
answered Oct 9, 2013 by sreemathi.v
 

Related questions

Ask Question
student study plans
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...