Chapter 13: Problem 29
Solve. Remember that graphs can be used to confirm all real solutions. $$ \begin{aligned} &x^{2}+y^{2}=9\\\ &x^{2}-y^{2}=9 \end{aligned} $$
Short Answer
Expert verified
The solutions are (3, 0) and (-3, 0).
Step by step solution
01
Understand the given equations
The exercise gives two equations: 1) The first equation is a circle equation: \( x^{2} + y^{2} = 9 \) 2) The second equation is a hyperbola equation: \( x^{2} - y^{2} = 9 \)
02
Add the two equations
To simplify the process, add the two given equations: \( x^{2} + y^{2} = 9 \) \( x^{2} - y^{2} = 9 \) Adding these equations results in: \( (x^{2} + y^{2}) + (x^{2} - y^{2}) = 9 + 9 \) \( 2x^{2} = 18 \) Simplify: \( x^{2} = 9 \) Take the square root of both sides: \( x = \text{±} 3 \)
03
Solve for y with each x value
Substitute \( x = 3 \) into the first equation: \( 3^{2} + y^{2} = 9 \) \( 9 + y^{2} = 9 \) \( y^{2} = 0 \) Thus, \( y = 0 \). Similarly, substitute \( x = -3 \) into the first equation: \( (-3)^{2} + y^{2} = 9 \) \( 9 + y^{2} = 9 \) \( y^{2} = 0 \) Thus, \( y = 0 \).
04
Confirm Solutions
The solutions are the points \( (3, 0) \) and \( (-3, 0) \).
05
Graphical Confirmation
Graph both equations on the same coordinate plane to see the points of intersection. The circle \( x^{2} + y^{2} = 9 \) and the hyperbola \( x^{2} - y^{2} = 9 \) intersect at the points \( (3, 0) \) and \( (-3, 0) \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Circle Equation
In mathematics, the equation of a circle is fundamental when dealing with geometric shapes. The standard form of a circle's equation is given by \( (x - h)^{2} + (y - k)^{2} = r^{2} \), where \( (h, k) \) represents the coordinates of the circle's center, and \( r \) is the radius. In our given problem, the circle's equation is \( x^{2} + y^{2} = 9 \). This means the circle is centered at the origin (0,0) with a radius of \sqrt{9} = 3\.
- The term \( x^{2} \) and \( y^{2} \) shows the distances from the center to any point on the circle remains constant.
- Adding or subtracting the same values to these squared terms shifts the circle around the coordinate plane accordingly.
Hyperbola Equation
Just as the circle has its standard equation, so does a hyperbola. The standard form of a hyperbola's equation is usually given by \( \frac{x^{2}}{a^{2}} - \frac{y^{2}}{b^{2}} = 1 \) for horizontal hyperbolas or \( \frac{y^{2}}{a^{2}} - \frac{x^{2}}{b^{2}} = 1 \) for vertical hyperbolas.
In our problem, we have \( x^{2} - y^{2} = 9 \), which aligns with the horizontal hyperbola centered at the origin (0,0) and transverse axis along the x-axis. To match the given equation with the standard form, we can rewrite it as \( \frac{x^{2}}{9} - \frac{y^{2}}{9} = 1 \).
In our problem, we have \( x^{2} - y^{2} = 9 \), which aligns with the horizontal hyperbola centered at the origin (0,0) and transverse axis along the x-axis. To match the given equation with the standard form, we can rewrite it as \( \frac{x^{2}}{9} - \frac{y^{2}}{9} = 1 \).
- This tells us that \ a^{2} = 9 \ and \right and left-transversal axis length is 2a = 6,
- and b=b=3 indicating vertical with asymptotes y=±3 This information is key for drawing the hyperbola and understanding its intersections with other shapes.
Graphical Confirmation
Graphical confirmation is a powerful step in solving and verifying solutions to equations. By plotting both the circle \( x^{2} + y^{2} = 9 \) and the hyperbola \( x^{2} - y^{2} = 9 \) on the same coordinate plane, we can visually confirm the points of intersection.
Here’s how we do it:
This graphical method gives a clear visual representation, confirming the accuracy of algebraic solutions.
Here’s how we do it:
- First, we draw the circle with center (0,0) and radius 3.
- Next, we draw the hyperbola, also centered at (0,0) with a transverse axis of 6 and asymptotes along the lines \ y = \ ✓3.
This graphical method gives a clear visual representation, confirming the accuracy of algebraic solutions.