Bahas PR Bareng

Question 1 Solution: We need to declare:  $$A=\begin{bmatrix}2\\7\end{bmatrix}, B=\begin{bmatrix}10\\2\end{bmatrix}, C=\begin{bmatrix}7\\4\end{bmatrix}$$ And then find \(\overrightarrow {AB}\) and \(\vec N\): $$\overrightarrow {AB}=\begin{bmatrix}10-2\\2-7\end{bmatrix}=\begin{bmatrix}8\\-5\end{bmatrix}$$ Here are some basic rule you need to know to easily define \(\vec N\): $$if \ \vec N \ is \ to \ the \ left \ of \ any \ vector \rightarrow \vec N=\begin{bmatrix}-dy\\dx\end{bmatrix}$$  $$if \ \vec N \ is \ to \ the \ right \ of \ any \ vector \rightarrow \vec N=\begin{bmatrix}dy\\-dx\end{bmatrix}$$ From the rule above, we can see that because \(\vec N\) is facing to the left (up as stated in the question) of \(\overrightarrow {AB}\), we can conclude as stated below: $$\vec N=\begin{bmatrix}-dy\\dx\end{bmatrix}=\begin{bmatrix}5\\8\end{bmatrix}$$ Variable \(dx\) and \(dy\) is taken from \(\overrightarrow {AB}\). After that the question requires us to ...