A) \[2r\sin \left( \frac{\theta }{2} \right)\]
B) \[2r\cos \left( \frac{\theta }{2} \right)\]
C) \[2r\tan \left( \frac{\theta }{2} \right)\]
D) \[2r\cot \left( \frac{\theta }{2} \right)\]
Correct Answer: A
Solution :
\[\Delta r={{r}_{2}}-{{r}_{1}}\] Where, \[{{r}_{2}}={{r}_{1}}=r\] Hence \[\Delta r=\sqrt{r_{1}^{2}+r_{2}^{2}-2{{r}_{1}}{{r}_{2}}\cos \theta }\] \[=2r\sin \frac{\theta }{2}\]You need to login to perform this action.
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