let v=i+j+k and w=-2i -k find the magnitude of the projection of w onto v

Question

I thought i use the equation proj w onto v= (v.w)/lvl so i got -3/sqrt3 but the answer is 1/sqrt 3

Answer 1

Hmmm. Your answer looks good to me.
Although, I'd simplify it to just

3/√3 = √3