XI_Trigonometric Functions_3

 $If\ \tan x=\frac{1}{2}and\ \tan y=\frac{1}{3},$  then the value of x + y is

•  $\frac{\pi}{6}$  

•  $\pi$  

•  $0$  

•  $\frac{\pi}{4}$  

 $\frac{\cos10^o+\sin10^o}{\cos10^o-\sin10^o}=$  

•  $\tan55^o$  

•  $\cot55^o$  

•  $-\tan35^o$  

•  $-\cot35^o$  

 $If\ A+B=\frac{\pi}{4},\ then\ \left(1+\tan A\right)\left(1+\tan B\right)=$  

• 2

• 1

• 3

• 0

 $\frac{\tan69^o+\tan66^o}{1-\tan69^o\tan66^o}=$  

• 1

• - 1

• 0

• none of these

 $The\ value\ of\ \sin50^o-\sin70^o+\sin10^o=$  

• 1

• 0

• 1/2

• 2

Which of the following is not correct?

• $\sin x=-\frac{1}{2}$

• $\cos x=1$

• $\sec x=\frac{1}{2}$

• $\tan x=20$

 $The\ value\ of\ \frac{1-\tan^215^o}{1+\tan^215^o}is$  

• 1

•  $\sqrt{3}$  

•  $\frac{\sqrt{3}}{2}$  

• 2