| In \[\Delta ABC\], if\[AB=2BC\], \[\angle B=90{}^\circ \], then the value of sec A is |
 |
A) \[\frac{1}{\sqrt{2}}\]
B) \[\frac{\sqrt{3}}{2}\]
C) \[\frac{\sqrt{5}}{2}\]
D) \[\frac{1}{2}\]
Correct Answer: C
Solution :
| Given, \[AB=2BC\] |
| \[\frac{AB}{BC}=2\] |
| \[\tan \,A=\frac{BC}{AB}=\frac{1}{2}\] |
| Let \[AB=2k\] and \[BC=k\] |
| \[AC=\sqrt{4{{k}^{2}}+{{k}^{2}}}=\sqrt{5}k\] |
| \[\sec A=\frac{AC}{AB}=\frac{\sqrt{5}k}{2k}=\frac{\sqrt{5}}{2}\] |
You need to login to perform this action.
You will be redirected in
3 sec
