To determine the interval where $h(x) < 0$ based on the graph provided, we need to find where the graph of the function $h(x)$ is below the x-axis.

From the graph, the function is below the x-axis in the following intervals:

1. From approximately $x \approx -4$ to $x \approx -3$.
2. From approximately $x \approx -1$ to $x \approx 1$.
3. From approximately $x \approx 3$ to $x \approx 4$.

These intervals indicate the sections where $h(x) < 0$.

Would you like more details or have any questions?

Here are some related questions that expand on this information:

1. How do we find where a function is positive or negative from its graph?
2. What is the significance of the x-intercepts in determining intervals where the function is negative?
3. How can we algebraically determine the intervals where a function is negative if the function's equation is given?
4. What other properties can be deduced from the graph, such as maxima, minima, or points of inflection?
5. How do changes in the amplitude or frequency affect the intervals where a sinusoidal function is below zero?

Tip: When identifying intervals on a graph, always look for points where the curve intersects the x-axis, as these are the boundaries where the function changes from positive to negative or vice versa.