Given:-
![<1,5>,<3,15>](https://img.qammunity.org/2023/formulas/mathematics/college/f3gz9qmsx7zhu0g74wecmr2ziet93t08q6.png)
To find:-
The given vectors are parallel, orthogonal or neither.
So now we check, the given vectors is orthogonal or not.
![\begin{gathered} \bar{u}\bar{.v}=1(3)+5(15) \\ \text{ =3+75} \\ \text{ =78} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/c9l5rtvb532e189uoh7xuskwjkzo6sh95c.png)
The given vectors are not orthogonal because if the vectors are orthogonal the dot product should be zero.
So now we check, the given vectors is parallel or not,
![\begin{gathered} \lvert u\rvert=\sqrt[]{1^2+5^2} \\ \text{ =}\sqrt[]{1+25} \\ \text{ =}\sqrt[]{26} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/qz4x4l58vre87avkqc9sgrge1pz2d5q50m.png)
Also,
![\begin{gathered} \lvert v\rvert=\sqrt[]{3^2+15^2} \\ \text{ =}\sqrt[]{9+225} \\ \text{ =}\sqrt[]{234} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/zez3y0svtgaefcwii6w2wrddowwrprb8at.png)
So now,
![\begin{gathered} \theta=\cos ^(-1)((u.v)/(\lvert u\rvert\lvert v\rvert)) \\ \theta=\cos ^(-1)(\frac{78}{\sqrt[]{26}\sqrt[]{234}}) \\ \theta=\cos ^(-1)((78)/(5.099*15.29)) \\ \theta=\cos ^(-1)(1) \\ \theta=90 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5dsibje4qej4wtjcyherce31f0c4muaylt.png)
So we get the value of theta as 90 degree. So the given vectors are Parallel.