A) \[\frac{\sqrt{3}-1}{2\sqrt{2}}\]
B) \[\frac{\sqrt{3}-1}{\sqrt{2}}\]
C) \[-\frac{\sqrt{3}-1}{\sqrt{2}}\]
D) \[\frac{\sqrt{3}+1}{\sqrt{2}}\]
Correct Answer: C
Solution :
Consider \[\cos {{225}^{o}}+\sin {{195}^{o}}\] \[=\cos ({{270}^{o}}-{{15}^{o}})+\sin ({{180}^{o}}+{{15}^{o}})\] \[=-\sin {{15}^{o}}-\sin {{15}^{o}}\] \[=-2\sin {{15}^{o}}=-2\left( \frac{\sqrt{3}-1}{2\sqrt{2}} \right)=-\left( \frac{\sqrt{3}-1}{\sqrt{2}} \right)\]
You need to login to perform this action.
You will be redirected in
3 sec
