Calculation of shortest distance when one in symmetric form amd other in unsymmetric form

Reduction of unsymmetrical form into symmetrical form

Write the symmetric form of the equation of a line.

Shortest distance between two skew lines in vector + cartesian form

What is the equation of x-axis in symmetric form.

Shortest distance between two parallel lines in vector + cartesian form

What is the symmetric form of the equation of z-axis ?

Two plane mirrors are placed parallel to each other. The distance between the mirrors is 10cm. An object is placed between the mirrors at a distance of 4cm from one of them, say M_(1) . What is the distance between the first time formed at M_(1) and the second image formed at M_(2) ?

Two plane mirrors are placed parallel to each other. The distance between the mirrors is 10cm. An object is placed between the mirrors at a distance of 4cm from one of them, say M_(1) . What is the distance between the first time formed at M_(1) and the second image formed at M_(2) ?