# Parellel position vectors in mechanics

#### Vikash

##### New member
My dought is ....given that c=3i+4j and d=i-2j FIND μ if μc+d is parellel to i+3j.
First step : μ (3i +4j ) + i-2j
3μi + 4μj +
i - 2j
I dont understand what is the next step after this and how to solve this....what do you mean by parellel to this vector and how do you go about solving this....HELP IS REALLY APPRECIATED PLEASE.....

#### Harry_the_cat

##### Senior Member
Any vector which is parallel to another will be a scalar multiple. So any vector parallel to i + 3j will be of the form ki +3kj where k is a real number.
Does that help?

#### Vikash

##### New member
Any vector which is parallel to another will be a scalar multiple. So any vector parallel to i + 3j will be of the form ki +3kj where k is a real number.
Does that help?
Ok after that how to interpret this idea into the question ?

#### Harry_the_cat

##### Senior Member
Take your 3ui+4uj+i-2j = ??i + ??j then equate the coefficients of i and of j with ki+3kj.
You will then have two equations with two variables, u and k, to solve simultaneously. You really only need u to answer your question, but I would calculate k as well and use it to check your answer.