The graph shows the number of game systems sold since 2015. Based on this information, which function best models the number of game systems sold in millions `x` years since 2015?

1 answer

To determine the function that best models the number of game systems sold since 2015, we need to carefully examine the graph depicting the sales data over time. The type of function that is appropriate depends on the pattern of the data points.

Here are some common types of functions that might be considered:

1. **Linear Function**: This function is in the form \( y = mx + b \), where \( m \) is the slope and \( b \) is the y-intercept. A linear model suggests a constant rate of change.
- If the graph shows a straight line, a linear function might be the best fit.

2. **Quadratic Function**: This function is in the form \( y = ax^2 + bx + c \). A quadratic model is used when data shows a parabolic trend (i.e., it might be increasing or decreasing, then changing direction).
- If the graph shows a U-shaped or an inverted U-shaped curve, a quadratic function may be appropriate.

3. **Exponential Function**: This function is in the form \( y = a \cdot b^x \), where \( b \) is the base of the exponential growth or decay.
- If the graph shows rapidly increasing or decreasing sales, especially if the rate of change itself is changing, an exponential function might be the best fit.

4. **Logarithmic Function**: This function is in the form \( y = a \cdot \log_b(x) + c \).
- If the graph shows a quick increase or decrease that then levels off, a logarithmic function could model the trend.

5. **Piecewise Function**: This involves multiple functions for different sections of the graph.
- If the sales data shows different behaviors in different periods, a piecewise function might be the most applicable.

To select the best model, do the following:

1. **Visual Inspection**: Look at the shape of the graph.
- If it’s straight, lean towards a linear function.
- If it’s parabolic, consider a quadratic function.
- If it's rapidly increasing/decreasing, consider an exponential function.

2. **Statistical Methods**: Fit different models to the data and compute statistical measures such as the R-squared value to see which model fits best.

3. **Domain Knowledge**: Consider any external factors that might suggest a particular type of growth (e.g., market saturation might suggest a logarithmic model).

Without seeing the actual graph, summarized below are general suggestions based on common sales patterns:

- **Linear Model**: If the sales are consistently increasing or decreasing at a steady rate.
- **Quadratic Model**: If there is a peak or a trough in the sales data.
- **Exponential Model**: If there is rapid growth or decline.
- **Logarithmic Model**: If the sales increase rapidly initially and then level off.

For a precise recommendation, you'd need to plot the sales data points, fit these potential models, and evaluate their fit based on criteria such as the residual sum of squares (RSS) or the coefficient of determination (R-squared).

In conclusion, the best function to model the sales data depends on the pattern of the data points on the graph. Provide more specific details of the graph's shape for a more accurate function recommendation.