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MATH 1150 · Radical expressions · Objective 1.1

Square-Root Parent Function

Build the graph of y = √x from its domain and exact anchor points.

CLO 1 · Topic 9 of 21
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Build the concept from the beginning

Meaning before procedure

The parent square-root function f(x) = √x begins at (0,0), exists only for x ≥ 0, and increases while flattening. Perfect-square x-values create exact anchor points.

Parent function
The simplest function in a transformation family.
Endpoint
The starting point (0,0) of y = √x.
Domain
All allowed x-values: x ≥ 0.
Range
All output values: y ≥ 0.

Interactive visual model

Adjust a, h, and k and compare the transformed curve with the square-root parent.

Change one control at a time and describe what changes—and what stays invariant.

A dependable four-step method

Choose perfect-square x-values.
Compute their principal square roots.
Plot the endpoint and anchor points.
Connect with an increasing, flattening curve only in the domain.
  1. Choose perfect-square x-values.
  2. Compute their principal square roots.
  3. Plot the endpoint and anchor points.
  4. Connect with an increasing, flattening curve only in the domain.
Three fully explained examples

Watch the reasoning, not just the answer

Example 1: Find three points on y = √x.

Name the goalUse perfect-square inputs.
Choose the next moveChoose x = 0, 1, 4.
Carry out the mathematicsThe points are (0,0), (1,1), and (4,2).
Check and interpretEach y-value squared reproduces its x-value.

Example 2: Determine whether (9,3) lies on y = √x.

Name the goalSubstitute x = 9.
Choose the next moveEvaluate the principal square root.
Carry out the mathematics√9 = 3, so the point lies on the graph.
Check and interpretThe coordinates satisfy y² = x with y ≥ 0.

Example 3: State the domain and range.

Name the goalUse the radicand restriction and principal-root output.
Choose the next moveRequire x ≥ 0 and note √x ≥ 0.
Carry out the mathematicsDomain [0,∞); range [0,∞).
Check and interpretThe graph begins at the origin and stays in the first quadrant.
Interactive practice

Predict, decide, check, and revise

Interactive construction lab

Build a valid reasoning path

Choose the decisions in the order a careful solver would use them for this concept.

Choose this step, then check the construction.
Choose this step, then check the construction.
Choose this step, then check the construction.

The reasoning path changes as each decision is selected.

Readiness check

Check the foundation

On y = √x, what y-value corresponds to x = 0?

On y = √x, what y-value corresponds to x = 1?

Not completed yet.
Guided practice

Apply the method with support

On y = √x, what y-value corresponds to x = 4?

On y = √x, what y-value corresponds to x = 9?

On y = √x, what y-value corresponds to x = 16?

Not completed yet.
Independent practice

Work without step prompts

On y = √x, what y-value corresponds to x = 25?

On y = √x, what y-value corresponds to x = 36?

On y = √x, what y-value corresponds to x = 49?

On y = √x, what y-value corresponds to x = 64?

Not completed yet.
Mastery check

Demonstrate durable understanding

On y = √x, what y-value corresponds to x = 81?

On y = √x, what y-value corresponds to x = 100?

On y = √x, what y-value corresponds to x = 121?

On y = √x, what y-value corresponds to x = 144?

On y = √x, what y-value corresponds to x = 169?

Not completed yet.
Unfamiliar transfer

Explain, compare, and revise

Explain how a table of perfect squares predicts the shape and direction of y = √x.

Write a first attempt before opening the self-check.

The learner record reveals exact answers and model reasoning only after an attempt.