Question

Why is this true?
\[\vec E \cdot d \vec l=E \hat i \cdot (dx \hat i +dy \hat j +dz \hat k)=E dx\]
I understand the first part
\[\vec E \cdot d \vec l=E \hat i \cdot (dx \hat i +dy \hat j +dz \hat k)\] but how does that equal Edx?

Answer 1

@zepdrix @hartnn

Answer 2

i and j are perpendicular
i and k are perpendicular

Answer 3

i.i = i^2 = 1
i.j =0
i.k=0

Answer 4

I'm sorry...but how did you determine that they were perpendicular?

Answer 5

i , j and k are standard unit vectors.
i is along x direction
j is along y direction
k is along z direction
and axes are perpendicular to each other, right ?

Answer 6

yes

Answer 7

any more doubts ?