Radius of a Circle: Solving Negative Equations

In summary, the equation for finding the radius of a circle is r = √(A/π), where r is the radius, A is the area of the circle, and π is the mathematical constant pi (approximately equal to 3.14). The radius of a circle cannot be negative as distance cannot be negative. When given a negative equation, you can use the absolute value to solve for the radius. A circle with a negative radius cannot be graphed, but an equation with a negative radius can be rewritten using absolute value to graph it. The radius of a circle can be imaginary in advanced mathematics, but in practical applications, it will always be a real number.
  • #1
chemic_23
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Homework Statement



circle.jpg


Homework Equations



Why is there negative on h-2k+2?and a denominator of negative square root of 5?
also in 2h-k-17, it has a negative sign but the denominator is not negative square root of 5? I really don't understand this part... please explain :frown:
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The Attempt at a Solution

 
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  • #2
In this problem center of the circle lies between the two tangents. In such cases, to find the perpendicular distances, you have to make the constant C in the tangent positive.
 
  • #3


I understand that negative numbers can be confusing, especially when they are used in equations. In this case, the negative sign in front of the equations indicates that the value is less than zero. In the first equation, h-2k+2, the negative sign is used to show that the value inside the parentheses is being subtracted from h, which means that it is being moved to the left on the number line. The denominator of negative square root of 5 is used to represent the square root of 5 with a negative value, which is the same as taking the square root of -5. This is because when a negative number is squared, the result is a positive number.

In the second equation, 2h-k-17, the negative sign in front of the equation indicates that the entire value is being subtracted from 0. The denominator is not a negative square root of 5 because the negative sign is not being used to represent a negative value in this case. Instead, it is being used to show that the value is being subtracted from 0, which means that it is being moved to the left on the number line.

Overall, the use of negative numbers in equations is important as it allows us to represent values that are less than zero and to perform operations such as subtraction and division. I hope this explanation helps to clarify any confusion you may have had about the negative signs in these equations.
 

1. What is the equation for finding the radius of a circle?

The equation for finding the radius of a circle is r = √(A/π), where r is the radius, A is the area of the circle, and π is the mathematical constant pi (approximately equal to 3.14).

2. Can the radius of a circle be negative?

No, the radius of a circle cannot be negative. The radius is a measurement of distance from the center of the circle to any point on its circumference, and distance cannot be negative.

3. How do you solve for the radius of a circle when given a negative equation?

To solve for the radius of a circle when given a negative equation, you can use the absolute value of the negative number. For example, if the equation is -r = 10, you would rewrite it as r = |-10|, which would give you a positive radius of 10.

4. How do you graph a circle with a negative radius?

A circle with a negative radius cannot be graphed, as the radius represents a distance and cannot be negative. However, if you are given an equation for a circle with a negative radius, you can rewrite it using the absolute value of the radius to graph it. For example, if the equation is x^2 + y^2 = (-5)^2, you would rewrite it as x^2 + y^2 = 25, which would give you a circle with a radius of 5.

5. Can the radius of a circle be imaginary?

Yes, the radius of a circle can be imaginary. This typically occurs when dealing with complex numbers in advanced mathematics. However, in practical applications, the radius of a circle will always be a real number.

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