Explanation:
For series
[tex]\Delta V=V_{1}+V_{2}+\ldots+V_{n}=I R_{1}+I R_{2}+\ldots+I R_{n}(\text {voltages add to the batter } y)[/tex]
[tex]\(I=I_{1}=I_{2}=I_{n}\) (current is the same)[/tex]
[tex]V=I R(\text {voltage is directly proportional to } R)[/tex]
[tex]R_{e q}=R_{1}+R_{2}+\ldots+R_{n} \quad \text { (resistance increase) }[/tex]
For parallel
[tex]\Delta V=\Delta V_{1}=\Delta V_{2}=\Delta V_{n} \quad(\text { same voltage })[/tex]
[tex]I=I_{1}+I_{2}+\ldots+I_{n}(\text {current adds})[/tex]
[tex]\(I=\frac{\Delta V}{R_{e q}} \quad(R \text { inversal } y \text { proportional to } I)\)[/tex]
[tex]\frac{1}{R_{e q}}=\frac{1}{R_{1}}+\frac{1}{R_{2}}+\ldots+\frac{1}{R_{n}}[/tex]