/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 64 Find the center and the radius o... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Find the center and the radius of each circle. Then graph the circle. $$4 x^{2}+4 y^{2}=1$$

Short Answer

Expert verified
Center: (0, 0). Radius: \( \frac{1}{2} \).

Step by step solution

01

Write the equation in standard form

The given equation is \[ 4x^{2} + 4y^{2} = 1 \]Divide every term by 4 to write it in the standard form of a circle’s equation: \[ x^{2} + y^{2} = \frac{1}{4} \]
02

Identify the center of the circle

The standard form of a circle’s equation is \[ (x - h)^{2} + (y - k)^{2} = r^{2} \]Here, we have \[ (x - 0)^{2} + (y - 0)^{2} = \frac{1}{4} \]So the center \( (h, k) \) is \( (0, 0) \).
03

Find the radius of the circle

In the standard form, \( r^{2} = \frac{1}{4} \).Taking the square root on both sides, \( r = \frac{1}{2} \).Thus, the radius is \( \frac{1}{2} \).
04

Graph the circle

Plot the center of the circle at \( (0, 0) \).From the center, mark points that are \( \frac{1}{2} \)units away in all directions (up, down, left, and right). Draw a smooth curve connecting these points to create the circle.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Standard Form of Circle
The standard form of a circle's equation helps to identify its center and radius easily. This form is written as \((x - h)^{2} + (y - k)^{2} = r^{2}\), where \(h\) and \(k\) are the coordinates of the circle's center and \(r\) is the radius. In our exercise, the given equation was \[ 4x^{2} + 4y^{2} = 1 \]. By dividing each term by 4, we simplified it to \(x^{2} + y^{2} = \frac{1}{4}\). This matches our standard form with \(h\) and \(k\) both equal to 0 and the radius squared \((r^{2})\) being \(\frac{1}{4}\).
Center of Circle
Locating the center of a circle is straightforward when the equation is in standard form. The general formula \((x - h)^{2} + (y - k)^{2} = r^{2}\) shows that \(h\) and \(k\) are the coordinates of the center. From our simplified equation \(x^{2} + y^{2} = \frac{1}{4}\), we see that \(h\) and \(k\) are both 0. This tells us the center of the circle is at the origin, \( (0, 0) \). Anytime we see \( (x - 0) \) and \( (y - 0) \), the translation to center coordinates is \( (0, 0) \).
Radius of Circle
The radius of a circle can be found by taking the square root of the \(r^{2}\) term in the standard form equation. In \((x - h)^{2} + (y - k)^{2} = r^{2}\), \(r^{2} = \frac{1}{4} \). To find \(r\), take the square root of \(\frac{1}{4} \):
\[ r = \frac{1}{2} \]
This \( \frac{1}{2} \) unit is the distance from the center of the circle to the border in any direction. Thus, the radius of the circle is \(\frac{1}{2}\) units.
Graphing Circles
To graph a circle, follow these simple steps:
  • Identify the center: In our case, it’s \( (0, 0) \).
  • Mark the center on the graph.
  • Measure the radius distance \( \frac{1}{2} \) units from the center in four directions: up, down, left, and right.
  • Place points at these distances.
  • Draw a smooth curve connecting these points, forming the circle.
Graphing becomes intuitive by practicing these steps: starting at the center, marking equal distances based on the radius, and connecting the dots smoothly to form the circle.

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