Consider the function \(f\colon y =\mathop{\mathrm{cotg}}\nolimits x\).
In the following list identify the function which has the same graph as the graph of the
function \(f\).
Consider the function \(f\colon y = A\cdot \sin (B\cdot x + C)\), with
real nonzero parameters \(A\),
\(B\) and
\(C\).
Which of the following operations makes the period of the function five times
smaller?