Final answer:
The minimum of a sinusoidal function is the negative value of its amplitude, indicated as -A.
Step-by-step explanation:
The minimum of a sinusoidal function, such as a sine or cosine function, represents the lowest point on the function's graph. Given a sine function in the form y(x, t) = A sin(kx - ωt + φ), where A is the amplitude, k is the wave number, ω is the angular frequency, and φ is the phase shift, the minimum value will be -A. This is because the sinusoidal function oscillates between +A and -A, so the minimum value the function can reach is its amplitude with a negative sign.