1.

Find k for the given planes x + 2y + kz + 2 = 0 and 3x + 4y – z + 2 = 0, if they are perpendicular to each other.(a) 21(b) 17(c) 12(d) 11The question was posed to me in final exam.Query is from Three Dimensional Geometry topic in chapter Three Dimensional Geometry of Mathematics – Class 12

Answer»

Correct choice is (d) 11

Easy explanation: Relation between the the planes a1x + b1y + c1z + D1 = 0 and a2x + b2y + c21z + D2 = 0, if their NORMAL are perpendicular to each other is A1A2 + b1b2 + c1c2 = 0.

1(3) + 2(4) + k(-1) = 0

k(-1) = -11

k = 11



Discussion

No Comment Found

Related InterviewSolutions