The problem gives two quadratic functions $f(x) = 2ax^2 + (2a+1)x + a$ and $g(x) = -ax^2 - x - 1$. (1) We need to find the expression for $f(x) - g(x)$ in the form $Jax^2 + K(a+L)x + a + M$ and determine the values of $J, K, L, M$. (2) Using the result from (1), we need to find the range of values of $a$ for which the two parabolas $y=f(x)$ and $y=g(x)$ have no intersection points. We are given options for the range of $a$.
2025/6/10
1. Problem Description
The problem gives two quadratic functions and .
(1) We need to find the expression for in the form and determine the values of .
(2) Using the result from (1), we need to find the range of values of for which the two parabolas and have no intersection points. We are given options for the range of .
2. Solution Steps
(1) Calculate :
Comparing this with the given form , we have:
, , , .
So,
(2) The two parabolas and have no intersection points if and only if the equation has no real solutions. This is equivalent to having no real solutions.
Therefore, we need to find the values of for which the quadratic equation has no real solutions.
If , the equation becomes , which has a solution . So cannot be
0. If $a \ne 0$, the discriminant of the quadratic equation must be negative:
This inequality holds if either
(i) and , which means and , so and . Thus .
(ii) and , which means and , so and . Thus .
Therefore, the range of values of is or .
3. Final Answer
The range of is or , which corresponds to option (2).
Final Answer:
Option (2) is the correct one.