To determine the temperature yesterday, we need to find the average of today's temperature (0°C) and the temperature two days ago.
If we represent the temperature two days ago as (x, y), where x represents the time elapsed and y represents the temperature, we can assume that x = -2 as it represents two days ago.
Since the temperature two days ago is right in between today's temperature (0°C) and the temperature two days ago (x, y), we can express it as the midpoint between these two points.
The midpoint formula is as follows:
midpoint = ((x1 + x2) / 2, (y1 + y2) / 2)
Substituting the known values:
midpoint = ((0 + -2) / 2, (0 + y) / 2)
midpoint = (-2/2, y/2)
Since the midpoint is (-1, y/2), we know that y/2 represents the temperature yesterday.
Since the temperature yesterday is y/2 and the temperature today is 0°C, we can set up the equation:
y/2 = 0
Multiplying both sides of the equation by 2, we get:
y = 0
Therefore, the temperature yesterday was 0°C.