To solve the system of equations given by:
- \((x-2)^2 + y^2 = 9\) (this is the equation of a circle with center at (2, 0) and radius 3)
- \(y = x^2 - 4x + 4\) (this is a quadratic equation, which can also be expressed as \(y = (x-2)^2\), a parabola with vertex at (2,0))
we'll substitute the expression for \(y\) from the second equation into the first equation.
Step 1: Substitute for \(y\)
Substituting \(y = (x-2)^2\) into the first equation:
\[ (x-2)^2 + ((x-2)^2)^2 = 9 \]
Step 2: Simplify
Let \(u = (x-2)^2\). The equation now becomes:
\[ u + u^2 = 9 \]
This can be rearranged to form a standard polynomial equation:
\[ u^2 + u - 9 = 0 \]
Step 3: Solve the quadratic
We will use the quadratic formula \(u = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\) where \(a = 1\), \(b = 1\), and \(c = -9\):
\[ u = \frac{-1 \pm \sqrt{1^2 - 4 \cdot 1 \cdot (-9)}}{2 \cdot 1} \] \[ u = \frac{-1 \pm \sqrt{1 + 36}}{2} \] \[ u = \frac{-1 \pm \sqrt{37}}{2} \]
This gives us two possible values for \(u\):
\[ u_1 = \frac{-1 + \sqrt{37}}{2} \] \[ u_2 = \frac{-1 - \sqrt{37}}{2} \quad (\text{this value is negative and can be discarded since } u = (x-2)^2 \geq 0) \]
So we only consider:
\[ u = \frac{-1 + \sqrt{37}}{2} \]
Step 4: Find \(x\)
Recall that \(u = (x-2)^2\):
\[ (x-2)^2 = \frac{-1 + \sqrt{37}}{2} \]
Taking the square root of both sides gives:
\[ x - 2 = \pm \sqrt{\frac{-1 + \sqrt{37}}{2}} \]
So we have:
\[ x = 2 + \sqrt{\frac{-1 + \sqrt{37}}{2}} \quad \text{and} \quad x = 2 - \sqrt{\frac{-1 + \sqrt{37}}{2}} \]
Step 5: Find \(y\)
Now, substitute \(x\) back into \(y = (x-2)^2\):
For each value of \(x\):
- \(y_1 = (2 + \sqrt{\frac{-1 + \sqrt{37}}{2}} - 2)^2 = \frac{-1 + \sqrt{37}}{2}\)
- \(y_2 = (2 - \sqrt{\frac{-1 + \sqrt{37}}{2}} - 2)^2 = \frac{-1 + \sqrt{37}}{2}\)
Thus, the solutions to the system of equations are:
\[ \left(2 + \sqrt{\frac{-1 + \sqrt{37}}{2}}, \frac{-1 + \sqrt{37}}{2}\right) \]
and
\[ \left(2 - \sqrt{\frac{-1 + \sqrt{37}}{2}}, \frac{-1 + \sqrt{37}}{2}\right) \]
These are the intersection points of the circle and the parabola.
