Mathematics · essential
Condition for perpendicular lines for JEE
Direction ratios and direction cosines and the angle between two intersecting lines
Formula
\(a_1a_2+b_1b_2+c_1c_2=0\)
Variables: \((a_1,b_1,c_1)\), \((a_2,b_2,c_2)\) are direction ratios of the two lines.
Conditions: Both direction-ratio triples are nonzero.
Testing orthogonality of lines in 3D.