JAGJIT

First you have find the projection of u onto v to find u1. then you can simple subtract u from projection of u onto v to get your u2.

Thank you Arora, It works first find the two vectors with the above points: (0,2,-1)-(2,4,-6) = (-2,-2,5) [3,5,1]-[2,4,-6] = [1,1,7] cross multiply the points (to get normal vector) and we get: 19i+19j+0k plug in the numbers: 19x+19y+0z=d find d: 19(0)+19...