Question

Latex:
The vector $\begin{pmatrix} k \\ 2 \end{pmatrix}$ is orthogonal to the vector $\begin{pmatrix} 3 \\ 5 \end{pmatrix}$. Find $k$.

Regular:
The vector <k, 2>, is orthogonal to the vector <3, 5>. Find k.

I can't seem to figure it out, I thought k would be 10/3

Answer 1

<k,2>•<3,5> = 0
3k+10 = 0
k = -10/3

gotta watch those ± signs!

Answer 2

Thanks!