Solving y = x²: Does a Point Exist Where y = -2?

Quadratic Functions with Range Analysis

Given the function:

y=x2 y=x^2

Is there a point for ? y=2 y=-2 ?

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Does the point exist?
00:03 Let's substitute appropriate values according to the given data, and solve to find the point
00:07 Any number squared will always equal a positive number
00:11 Therefore, the point doesn't exist
00:17 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Given the function:

y=x2 y=x^2

Is there a point for ? y=2 y=-2 ?

2

Step-by-step solution

To solve this problem, we'll follow these steps:

  • Step 1: Analyze the equation y=x2 y = x^2 .
  • Step 2: Investigate whether a negative y y -value is possible.

Now, let's work through each step:
Step 1: The function we have is y=x2 y = x^2 . This function is defined for all real numbers and always gives a non-negative value y y because squaring a real number cannot result in a negative number.

Step 2: We need to check whether y=2 y = -2 is possible by solving x2=2 x^2 = -2 . In the real number system, no real number x x satisfies this equation since the square of any real number is non-negative.
Therefore, there is no real point where y=2 y = -2 on the graph of the function y=x2 y = x^2 .

Therefore, the solution to the problem is No.

3

Final Answer

No

Key Points to Remember

Essential concepts to master this topic
  • Range Property: Squared values are always non-negative for real numbers
  • Technique: Set x2=2 x^2 = -2 and check if solution exists
  • Check: Verify minimum value occurs at vertex (0,0) where y ≥ 0 ✓

Common Mistakes

Avoid these frequent errors
  • Assuming negative y-values are possible for quadratic functions
    Don't think that y=x2 y = x^2 can equal -2 just because you can write the equation! Since any real number squared is non-negative, x20 x^2 \geq 0 always. Always remember that parabolas opening upward have a minimum y-value at their vertex.

Practice Quiz

Test your knowledge with interactive questions

Complete:

The missing value of the function point:

\( f(x)=x^2 \)

\( f(?)=16 \)

FAQ

Everything you need to know about this question

Why can't x² ever equal a negative number?

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When you square any real number, the result is always positive or zero. For example: 32=9 3^2 = 9 , (3)2=9 (-3)^2 = 9 , and 02=0 0^2 = 0 . There's no real number that gives a negative when squared!

What's the range of y = x²?

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The range is all y-values ≥ 0. The parabola has its lowest point at (0,0) and goes upward forever. So y can be 0, 1, 4, 100, but never -1, -2, or any negative value.

Could there be complex solutions to x² = -2?

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Yes! In the complex number system, x=±i2 x = ±i\sqrt{2} where i is the imaginary unit. But for real-valued functions like y=x2 y = x^2 , we only consider real solutions.

How do I find the minimum value of a parabola?

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For y=x2 y = x^2 , the vertex is at (0,0), which gives the minimum y-value of 0. The parabola opens upward, so this is the lowest point on the graph.

What if the question asked about y = 2 instead?

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Then we'd solve x2=2 x^2 = 2 , giving x=±2 x = ±\sqrt{2} . Since 2 is positive, real solutions exist! The points would be (2,2) (\sqrt{2}, 2) and (2,2) (-\sqrt{2}, 2) .

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