Find the Domain of y=-(x-12)²+2: Analyzing Input Values

Question

Find the positive and negative domains of the function below:

y=(x12)2+2 y=-\left(x-12\right)^2+2

Step-by-Step Solution

To solve this problem, follow these steps:

  • Step 1: Find the roots of the function. Set y=0=(x12)2+2 y = 0 = -\left(x-12\right)^2 + 2 .

  • Step 2: Rearrange and solve for x x : (x12)2+2amp;=0(x12)2amp;=2 \begin{aligned} -\left(x-12\right)^2 + 2 &= 0 \\ \left(x-12\right)^2 &= 2 \end{aligned} Solving gives x12=±2 x - 12 = \pm \sqrt{2} , resulting in roots x=12+2 x = 12 + \sqrt{2} and x=122 x = 12 - \sqrt{2} .

  • Step 3: Determine the intervals: xlt;122122lt;xlt;12+2xgt;12+2 \begin{aligned} x < 12 - \sqrt{2} \\ 12 - \sqrt{2} < x < 12 + \sqrt{2} \\ x > 12 + \sqrt{2} \end{aligned} Step 4: Test each interval to check the sign of y y : \begin{itemize}

  • For x < 12 - \sqrt{2} and x > 12 + \sqrt{2} , (x12)2 (x-12)^2 becomes larger than 2, so y=[(x12)2]+2 y= -[(x-12)^2] + 2 is negative.

  • For 12 - \sqrt{2} < x < 12 + \sqrt{2} , (x12)2 (x-12)^2 is less than 2, so y=[(x12)2]+2 y = -[(x-12)^2] + 2 is positive.

Thus, the function is negative for x > 12 + \sqrt{2} or x < 12 - \sqrt{2} , and positive for 12 - \sqrt{2} < x < 12 + \sqrt{2} .

Therefore, the positive and negative domains of the function are:

x > 12+\sqrt{2} or x < 0 : x < 12-\sqrt{2}

x > 0 : 12-\sqrt{2} < x < 12+\sqrt{2}

Answer

x > 12+\sqrt{2} or x < 0 : x < 12-\sqrt{2}

x > 0 : 12-\sqrt{2} < x < 12+\sqrt{2}