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electromagnetics question ,plsss help me guys?
given two vectors rA= -ax-3ay-4az and rB=2ax+2ay+2az
find rab
and the answer is
RAB =(2+1)ax +(2+3)ay +(2+4)az
RAB= 3ax+5ay+6az
now my question is about the signs..why the two vectors added with positive sign..isnt it that it should rab=(2-1)ax+ (2-3)ay+(2-4)az
pls help me how to add vectors..wheter from positive to negative..please explain it to me guysss.plsss
2 Answers
- 8 years agoFavorite Answer
"(2-1)ax+ (2-3)ay+(2-4)az" is not RAB this is RA+RB
RAB will be RB-RA and that would change all signs of RA
RB-RA= 2ax+2ay+2az - ( -ax-3ay-4az)= 2ax+2ay+2az+ ax+3ay+4az= (2+1)ax +(2+3)ay +(2+4)az
Both vector RA and RB are originating from origin, where RAB means the vector connecting head of RA to the head of RB, which will be RB-RA.
If you need more explanation, you may ask.
