Math Problem Statement

Find an equation of the inverse relation.

x equals y squared minus 2 yx=y2−2y

Question content area bottom

Part 1

Choose the correct equation below.

A.y equals x squared plus 2 x

y equals x squared plus 2 xy=x2+2x

B.y equals 2 x minus x squared

y equals 2 x minus x squaredy=2x−x2

C.xy squared equals negative 2 y

xy squared equals negative 2 yxy2=−2y

D.y equals x squared minus 2 x

y equals x squared minus 2 x

Solution

To find the inverse of the relation given by:

x=y22yx = y^2 - 2y

we need to solve for yy in terms of xx and then interchange xx and yy to find the inverse.

Step 1: Rewrite the Equation in Terms of yy

The original equation is: x=y22yx = y^2 - 2y

Rearrange it to form a quadratic equation in terms of yy: y22yx=0y^2 - 2y - x = 0

Step 2: Solve for yy Using the Quadratic Formula

The quadratic formula is: y=b±b24ac2ay = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

For our equation y22yx=0y^2 - 2y - x = 0:

  • a=1a = 1
  • b=2b = -2
  • c=xc = -x

Substitute these values: y=2±(2)241(x)21y = \frac{2 \pm \sqrt{(-2)^2 - 4 \cdot 1 \cdot (-x)}}{2 \cdot 1} y=2±4+4x2y = \frac{2 \pm \sqrt{4 + 4x}}{2} y=2±21+x2y = \frac{2 \pm 2\sqrt{1 + x}}{2} y=1±1+xy = 1 \pm \sqrt{1 + x}

Step 3: Determine the Branch of the Solution

Since we are solving for the inverse, we select only one branch of the solution. Let’s assume y=1+1+xy = 1 + \sqrt{1 + x} (the other branch would represent another solution that might not satisfy the inverse relation contextually).

Step 4: Interchange xx and yy for the Inverse

Now, let y=xy = x and x=1+1+yx = 1 + \sqrt{1 + y}, so: y=1+1+xy = 1 + \sqrt{1 + x}

Answer Selection

The correct answer is: None of the choices match this exact equation. Please confirm if the given answers need adjustment.

Would you like further clarification on any steps?


  1. How do you determine the correct branch in finding the inverse?
  2. Why did we interchange xx and yy in the final answer?
  3. What is the significance of the quadratic formula in finding inverses?
  4. How do we interpret extraneous solutions in inverse functions?
  5. What would happen if we chose the other branch?

Tip: Always check solutions against the context given in inverse functions, especially when square roots are involved.

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Math Problem Analysis

Mathematical Concepts

Algebra
Inverse Functions
Quadratic Equations

Formulas

Quadratic formula: y = (-b ± √(b^2 - 4ac)) / 2a

Theorems

Quadratic formula for solving quadratic equations

Suitable Grade Level

Grades 9-12