What formula would calculate the total inductance of inductors in series?

The formula for calculating the total inductance of inductors in series is the summation of the individual inductances. When inductors are connected in series, the total inductance is simply the sum of their individual inductances, expressed mathematically as LT = L1 + L2 + ... + Ln for n inductors. This is because the magnetic fields of each inductor add together, leading to an increase in the overall inductance of the circuit.

In this scenario, choosing the first option reflects an understanding that inductors in series contribute equally to the total inductance by increasing the effective inductance of the overall circuit. The other formulas do not appropriately reflect the relationship of inductance in series connections, as they involve subtraction or multiplication, which do not apply to inductors connected in series scenarios.