The problem defines a function $g(\theta)$ in terms of a determinant $f(\theta)$. We are given $g(\theta) = \sqrt{f(\theta)-1} + \sqrt{f(\pi/2 - \theta) - 1}$, where $f(\theta)$ is a determinant of a $3 \times 3$ matrix. We are also given that $p(x)$ is a quadratic polynomial whose roots are the maximum and minimum values of $g(\theta)$, and $p(2) = 2 - \sqrt{2}$. We need to determine which of the given inequalities involving $p(x)$ are true.
2025/6/11
1. Problem Description
The problem defines a function in terms of a determinant . We are given , where is a determinant of a matrix. We are also given that is a quadratic polynomial whose roots are the maximum and minimum values of , and . We need to determine which of the given inequalities involving are true.
2. Solution Steps
First, let's compute :
Now, let's compute :
Therefore,
We need to find the maximum and minimum values of .
Note that . We can also calculate the derivative:
Setting , either , or
If , then or , so or .
If , then , so , meaning .
Since , .
When , .
When , .
When , .
Since and , the maximum value is when , and the minimum value is when or . This is incorrect because is the min and is the max.
When , . When , . When , .
Thus, minimum = and maximum is .
Since the roots of are and , for some constant .
We are given . Thus,
Since , .
It turns out the roots are minimum and maximum so the shape of the graph is upside down and a is negative. Thus .
so
Since , is a downward-facing parabola. The roots are and .
.
A. . . Since is less than the roots, we expect is negative.
B. . .
C. . .
D. . .
Since and , and knowing a is negative () then values outside of this range make . Values inside this range make .
since which is less than and .
since which is less than and .
Options A and D are correct.
3. Final Answer
A, D