Find the positive and negative domains of the function below:
y=(x+4)2−1041
To determine the positive and negative domains of the function, follow these steps:
- Step 1: Solve (x+4)2=441.
- Step 2: This implies x+4=±241.
- Step 3: Solving these gives the roots: x=2−8+41 and x=2−8−41.
- Step 4: Divide the real number line using these roots into intervals:
- Interval 1: x<2−8−41
- Interval 2: 2−8−41<x<2−8+41
- Interval 3: x>2−8+41
- Step 5: Test each interval to see where the function is greater or less than zero, using the sign of (x+4)2−441.
Testing reveals that:
- For Interval 1, the function is positive.
- For Interval 2, the function is negative.
- For Interval 3, the function is positive.
Thus, the negative domain is 2−8−41<x<2−8+41 and the positive domains are x>2−8+41 or x<2−8−41.
Therefore, the correct answer is:
x<0:2−8−41<x<2−8+41
x>2−8+41 or x>0:x<2−8−41
x < 0 :\frac{-8-\sqrt{41}}{2} < x < \frac{-8+\sqrt{41}}{2}
x > \frac{-8+\sqrt{41}}{2} or x > 0 : x < \frac{-8-\sqrt{41}}{2}