Question

Anyone know the answer to this?
http://imgur.com/pFutb59

@Preetha
@Michele_Laino

Answer 1

I think it's c equal.

Answer 2

hint:
if we identify your points using vectors, then we can write:
\[\Large R = Q + S\]

Answer 3

I think it's A then.

Answer 4

Never mind i am wrong it's D.

Answer 5

Am i correct? @Mich

Answer 6

here is my answer:
we can write:
\[RS = S - R = Q\]
so using the scalar or dot product, we have;
\[RS \cdot {\mathbf{\hat x}} = \left( {S - R} \right) \cdot {\mathbf{\hat x}} = Q \cdot {\mathbf{\hat x}}\]
then we have:
\[PS \cdot {\mathbf{\hat x}} = \left( {S - P} \right) \cdot {\mathbf{\hat x}} = Q \cdot {\mathbf{\hat x}}\]
please note that the scalar product is proportional to the cos of angle enclosed by the vectors to which that scalr product refers

Answer 7

oops..I have made a typo, the second formula is:
\[PQ \cdot {\mathbf{\hat x}} = \left( {Q - P} \right) \cdot {\mathbf{\hat x}} = Q \cdot {\mathbf{\hat x}}\]