Final answer:
The voltage across an inductor can be determined using the formula V = -L(dI/dt), where V is the voltage, L is the inductance, and dI/dt is the rate of change of current. However, without the current function, we cannot evaluate the expression or plot the graphs of i(t) and u(t).
Step-by-step explanation:
For an inductor, the voltage can be determined using the formula V = -L(dI/dt), where V is the voltage, L is the inductance, and dI/dt is the rate of change of current with respect to time. In this case, the inductor has an inductance of 100mH, which is equivalent to 0.1H. To evaluate the expression, we need to know the current function i(t).
Unfortunately, the current function is not provided in the question. Without the current function, we cannot determine the voltage across the inductor or plot the graphs of i(t) and u(t) on the same coordinate axes.