To determine the frequency of a sinusoidal function from a graph, you'll need to observe the number of complete cycles the wave completes over a certain interval—usually one second if time is on the x-axis. The frequency is the reciprocal of the period, which is the length of one complete cycle.

Here is a step-by-step guide on how you could find the frequency if looking at a graph:

1. Identify the Period: Look at the graph and determine the distance (along the x-axis) between two successive points where the wave begins repeating itself. These points could be consecutive peaks, troughs, or any identical points following the wave's pattern. Measure this distance; that is the period of the function.

2. Calculate the Frequency: The frequency (f) is the reciprocal of the period (T). If the period is measured in seconds, frequency will be in hertz (Hz), given by the formula: $f = \frac{1}{T}$

3. Round to the Nearest Whole Number: Once you compute the frequency, round the result to the nearest whole number.

Without seeing the actual graph, I cannot provide a specific numerical answer, but these steps will allow you to find the frequency using the graph.