1.A given line is described by the system of equations x=2t+7; y=-3t+4; z=5-t; find the equation of a line parallel to the given line and which contains the point (1,1,0).

Question

2.Let a=<0,6,2> and b=<0,2,4>, then the component of a parallel to b is given by?
- the answer is <0,2,4> but I do not understand why

Answer 1

Also, I do not understand how to add magnitudes.
Please help.

Let u and w be vectors in R3 such that ||u||=3 and ||w||=2 and the angle between the vectors is pi/2; what is the value of ||3u-4w||?
- answer is sqrt(145)