A) \[\frac{1}{\sqrt{3}}\]
B) \[\sqrt{3}\]
C) \[\frac{1}{2}\]
D) 1
Correct Answer: A
Solution :
\[\frac{\cos 15{}^\circ -\sin 15{}^\circ }{\cos 15{}^\circ +\sin 15{}^\circ }\] Divide numerator and denominator by \[\cos 15{}^\circ \] \[=\frac{1-\tan 15{}^\circ }{1+\tan 15{}^\circ }=\frac{\tan 45{}^\circ -\tan 15{}^\circ }{1+\tan 45{}^\circ \tan 15{}^\circ }=\tan \,\,(45{}^\circ -15{}^\circ )\] \[=\tan 30{}^\circ =\frac{1}{\sqrt{3}}\]
You need to login to perform this action.
You will be redirected in
3 sec
