[Math] Finding parametric equations given a point, orthogonal to another vector, and contained in a plane

parametricvectors

Find parametric equations for the line with the following properties. The line passes through the origin, it is contained in the plane $x-2y+z=0$, and is orthogonal to the vector $v = \langle3,4,2\rangle$.

I know that the vector is orthogonal to $v$ when the dot product of the vector I am looking for and $v$ is equal to $0$. But, how would I make sure that said vector is also meeting the other requirements?

Best Answer

The parametric equations will be of the form

$$x=0+at $$ $$y=0+bt $$ $$z=0+ct$$ with

$$3a+4b+2c=0$$ and $$at-2bt+ct=0$$

thus

$$a=2b-c $$ and

$$6b-3c+4b+2c=0$$ which gives $$c=10b $$ and $$a=-8b $$ finally, we get

$$x=-8t $$ $$y=t $$ $$z=10t $$