The Heaviside function \(\mathrm{H}\) is defined by
$$H(t)=\left\\{\begin{array}{ll}{0} & {\text { if } t<0} \\ {1} & {\text { if
} t \geqslant 0}\end{array}\right.$$
\(\begin{array}{l}{\text { It is used in the study of electric circuits to
represent the sudden }} \\ {\text { surge of electric current, or voltage,
when a switch is instantane- }} \\ {\text { ously turned on. }}\end{array}\)
\(\begin{array}{l}{\text { (a) Sketch the graph of the Heaviside function. }}
\\\ {\text { (b) Sketch the graph of the voltage V(t) in a circuit if the }}
\\\ {\text { switch is turned on at time } t=0 \text { and } 120 \text { volts
are applied }} \\ {\text { instantaneously to the circuit. Write a formula
for } V(t) \text { in }} \\ {\text { terms of H(t). }}\end{array}\).
\(\begin{array}{l}{\text { (c) Sketch the graph of the voltage } V(t) \text {
in a circuit if the switch }} \\ {\text { is turned on at time } t=5 \text {
seconds and } 240 \text { volts are applied }} \\ {\text { instantaneously to
the circuit. Write a formula for V(t) in }} \\ {\text { terms of H(t). (Note
that starting at } t=5 \text { corresponds to a }} \\ {\text { translation.)
}}\end{array}\)