Body diagonals -- unit vector notation

[Iron_Man_123]

Homework Statement

I'm fully convinced that the zero values make sense, yet they are wrong, can somebody please explain why is that the case

Homework Equations

N/A

The Attempt at a Solution

Attempt in the image above

 

[haruspex]

(a,0,0) is the bottom, left and front vertex in the diagram, right? Where is the other end of the diagonal from there?

 

[Iron_Man_123]

(a,0,0) is the bottom, left and front vertex in the diagram, right? Where is the other end of the diagonal from there?

It's at the top right corner of the image, which has 0 x-coordinate, am i mistaken?

 

[haruspex]

It's at the top right corner of the image, which has 0 x-coordinate, am i mistaken?

That's right. The vector along that diagonal is the difference between the endpoints, as vectors.

 

[Iron_Man_123]

That's right. The vector along that diagonal is the difference between the endpoints, as vectors.

However, I wrote zero in the i component in the answer space to part (b), does that mean the computer system is wrong and I am right?

 

[haruspex]

However, I wrote zero in the i component in the answer space to part (b), does that mean the computer system is wrong and I am right?

No, zero is wrong. Write the vector expressions for the two endpoints of the diagonal and subtract the bottom left front one from the top right back one. No zeroes.