Question

Find the distance between points $P\left(2,-\frac{\pi }{6}\right)$ and $Q\left(3,\frac{\pi }{6}\right)$

• A. 7
• B. $\sqrt{7}$
• C. $\sqrt{19}$
• D. 19

Answer 1

Answer: (B)

$PQ=\sqrt{r_1^2+r_2^2-2r_1{r}_2\cos \left({\theta }_1-{\theta }_2\right)}$
$=\sqrt{4+9-6}=\sqrt{7}$