Mathematics · essential
Direction ratios of a line for JEE
Direction ratios and direction cosines and the angle between two intersecting lines
Formula
\((a,b,c)\propto\) any vector parallel to the line
Variables: \(a,b,c\) are direction ratios (d.r.s) of the line.
Conditions: Not all of \(a,b,c\) are zero.
Writing equations of lines, testing parallelism/perpendicularity, angle problems.