I have $2$ vectors : $U =(2,k)$ and $V = (3,5)$. I want to find the $k$ value when the angle between $U$ and $V$ is $60$ degrees.
This what I tried to do but I don't get the right answer :
$2\cdot3 + 5k = \sqrt{4+k^2} \cdot \sqrt{34} \cdot \cos60 \rightarrow 24k^2 +30.84k+5$