# Thread: Find two vectors perpendicular to a line

1. ## Find two vectors perpendicular to a line

This is a question from my calculus 3 class.

"Find two unit vectors in 2-space that are perpendicular to the line y = -5x + 1"

I have to do this without a dot product or any matrices. And so I'm lost as to what I have to do. Where do I begin is what I'm asking? I'm thinking I maybe have to make an initial vector along the line and then go from there? It's the rotation part that's tripping me up though.

2. Originally Posted by nautica17
"Find two unit vectors in 2-space that are perpendicular to the line y = -5x + 1"
You know that the slope of the line is $\displaystyle -5$ and the point $\displaystyle (0,1)$ is on the line.
The slope of the perpendicular is $\displaystyle \frac{1}{5}$.
Find two points one on each side of the line such that they and $\displaystyle (0,1)$ determine a slope of $\displaystyle \frac{1}{5}$.
Make unit vectors out of that.

3. Okay, thank-you, I'll work on that.

4. Edit: nevermind.