physics
posted by Abdela said yimer on .
Suppose vector A=3i2j, B= i4j and vector C are three vectors in xy plane with the property that vectors A+BC. What is the unit vector along vector C?

Don't you mean that A + B = C ?
A + B  C is not a property. It is a vector that depends upon what C is.
A "unit vector along C" will depend upon how C is defined. It will be a combination of i and j. It is hard to believe they are really asking for that. 
I bet Dr WLS is right and that  sign should be an = sign
making that assumption:
A + B = C = 2 i  6 j
so
we need a unit vector in the C direction
Find magnitude of i  3 j which is in C direction
sqrt (1^2 + 3^2) = sqrt (10)
so
(1/sqrt 10) i  (3/sqrt 10) j