## JenniferSmart1 Group Title 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? one year ago one year ago

1. JenniferSmart1 Group Title

@zepdrix @hartnn

2. hartnn Group Title

i and j are perpendicular i and k are perpendicular

3. hartnn Group Title

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

4. JenniferSmart1 Group Title

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

5. hartnn Group Title

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 ?

6. JenniferSmart1 Group Title

yes

7. hartnn Group Title

|dw:1361080799293:dw| any more doubts ?

8. JenniferSmart1 Group Title

ahhhh.....nope...no more doubts =D