PQRS is a parallelogram. If \(\overrightarrow{\text{PR}}=\vec{\text{a}}\) and \(\overrightarrow{\text{QS}}=\vec{\text{b}}\), then what is \(\overrightarrow{\text{PQ}}\) equal to ?
1
\(\vec{\text{a}}+\vec{\text{b}}\)
2
\(\vec{\text{a}}−\vec{\text{b}}\)
3
\(\frac{\vec{\text{a}}+\vec{\text{b}}}{2}\)
4
\(\frac{\vec{\text{a}}−\vec{\text{b}}}{2}\)