+1855 Let $O$ be the origin. Points $P$ and $Q$ lie in the first quadrant. The slope of line segment $\overline{OP}$ is $4,$ and the slope of line segment $\overline{OQ}$ is $5.$ If $OP = OQ,$ then compute the slope of line segment $\overline{PQ}.$
Note: The point $(x,y)$ lies in the first quadrant if both $x$ and $y$ are positive.
+1950 Let's use trig.
slopePQ=−1/tan[(arctan(4)+arctan(5))/2]=[19−√442]/9≈−0.225
Thus, our answer is -0.225.
Thanks! :)
