Let the function be defined by
Define . Let α denote the number of solutions of the equation g(x) = 0 in the interval and . Then the value of α + β is equal to ______.
Correct Answer :
Solution :
First, let us analyze the definition of the function .
For odd integers of the form where , we have:
Evaluating this at consecutive values of gives:
- For :
- For :
- For :
- For :
For open intervals , the function is defined as:
This expression represents the linear interpolation between the points and . Thus, the function is a continuous, piecewise linear (sawtooth-like) function connecting the vertices:
Let us determine the value of :
Since , by the definition of the derivative and the Fundamental Theorem of Calculus:
Next, let us analyze the equation for .
1. For the interval :
The line segment connecting and is given by:
Integrating to find on this interval:
Setting .
Since , this yields one solution: .
Note that .
2. For the interval :
The line segment connecting and is:
Integrating for :
Setting .
Since in this sub-interval, this yields the solution: .
Note that .
3. For the interval :
Due to symmetry and periodicity of the sawtooth function (shifted by 4 units), the behavior of on is identical to with :
.
Note that .
4. For the interval :
Since is linear from at to at , we have for all and .
Thus, the integral is strictly decreasing and negative for .
Therefore, there are no solutions to in the interval .
Combining the solutions in the interval , we find exactly three values: , , and .
Thus, the number of solutions is:
Finally, we calculate the sum :
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