The problem is to analyze the inequality $4x^2 + 8xy + 3y^2 > 0$. We want to determine the conditions on $x$ and $y$ that make this inequality true.
2025/7/7
1. Problem Description
The problem is to analyze the inequality . We want to determine the conditions on and that make this inequality true.
2. Solution Steps
We can factor the quadratic expression:
So, we have the inequality .
This inequality holds if both factors are positive or both factors are negative.
Case 1: Both factors are positive.
and
and , so
In this case, since is false, we need both inequalities to hold, so .
Case 2: Both factors are negative.
and
and , so
In this case, since , we need both inequalities to hold, so .
However, if , the inequality becomes , which is true for . Thus, can be non-zero when .
Combining these cases, we have or .
Notice that if , then implies .
If , then implies .
Also, if , we have , which is never true.
If , we have , which is not greater than
0. If $y = -\frac{2}{3}x$, we have $4x^2 - \frac{16}{3}x^2 + \frac{4}{3}x^2 = \frac{12 - 16 + 4}{3}x^2 = 0$, which is not greater than
0. Therefore the inequality holds if $y > -\frac{2}{3}x$ or $y < -2x$. We must also exclude the lines $y = -\frac{2}{3}x$ and $y=-2x$. Also exclude the point $(0,0)$.
3. Final Answer
The inequality holds if or . We must exclude the lines and . Also, we must exclude the point (0,0).