# Homework Help: Parametric Equation

1. Feb 28, 2014

### yazz912

1. The problem statement, all variables and given/known

Determine parametric equations of the line that Is perpendicular to the lines L1= 3t-2
2t
3t

L2= s-1
2s-7
3s-12

And passes through the point of intersection of lines L1 and L2

2. Relevant equations

Parametric equation format:
x= x_1 +at
y= y_1 +bt
z= z_1 +ct

3. The attempt at a solution

We'll I'm given 2 sets of lines, I know that for something to be perpendicular I have to have the negative reciprocal of the slope.

But should my first step be to find the point of intersection of L1 and L2? Would I do this by solving a system of equations?

2. Feb 28, 2014

### yazz912

3. Feb 28, 2014

### Staff: Mentor

Keep in mind that the lines are in three dimensions. If you have two vectors in space, a third vector that is perpendicular to the first two vectors can be obtained from the cross product.

4. Feb 28, 2014

### yazz912

Im sorry do you Mind elaborating a little bit more for me?
So does that mean I can choose any two vectors from those three lines and just cross? Do this for both L1 and L2?