Math Problem Statement

Which point on the curve y=square root x-2+1 is closest to the point (4, 1)? What is this minimum distance?

Solution

To find the point on the curve y=x2+1y = \sqrt{x - 2} + 1 that is closest to the point (4,1)(4, 1), we need to minimize the distance between any point (x,y)(x, y) on the curve and the given point (4,1)(4, 1).

Step 1: Distance Formula

The distance DD between a point (x,y)(x, y) and (4,1)(4, 1) is given by:

D=(x4)2+(y1)2D = \sqrt{(x - 4)^2 + (y - 1)^2}

Since y=x2+1y = \sqrt{x - 2} + 1, we substitute this into the distance formula:

D(x)=(x4)2+(x2+11)2D(x) = \sqrt{(x - 4)^2 + (\sqrt{x - 2} + 1 - 1)^2}

Simplify the expression:

D(x)=(x4)2+(x2)2D(x) = \sqrt{(x - 4)^2 + (\sqrt{x - 2})^2}

D(x)=(x4)2+(x2)D(x) = \sqrt{(x - 4)^2 + (x - 2)}

D(x)=x28x+16+x2D(x) = \sqrt{x^2 - 8x + 16 + x - 2}

D(x)=x27x+14D(x) = \sqrt{x^2 - 7x + 14}

Step 2: Minimizing the Distance

To find the minimum distance, we need to minimize D(x)D(x). However, since the square root is a monotonically increasing function, we can instead minimize the squared distance D2(x)=x27x+14D^2(x) = x^2 - 7x + 14.

Let:

f(x)=x27x+14f(x) = x^2 - 7x + 14

Step 3: Find the Critical Points

To find the critical points, we take the derivative of f(x)f(x) with respect to xx and set it to zero:

f(x)=2x7f'(x) = 2x - 7

Set f(x)=0f'(x) = 0:

2x7=02x - 7 = 0

x=72=3.5x = \frac{7}{2} = 3.5

Step 4: Verify if x=3.5x = 3.5 is within the domain

The curve y=x2+1y = \sqrt{x - 2} + 1 is defined for x20x - 2 \geq 0 or x2x \geq 2. Since 3.523.5 \geq 2, it is within the domain.

Step 5: Find the Corresponding yy and the Minimum Distance

Substitute x=3.5x = 3.5 into the curve equation to find yy:

y=3.52+1=1.5+1y = \sqrt{3.5 - 2} + 1 = \sqrt{1.5} + 1

Thus, the point on the curve closest to (4,1)(4, 1) is (3.5,1.5+1)\left(3.5, \sqrt{1.5} + 1\right).

Now, calculate the minimum distance:

Dmin=(3.54)2+(1.5+11)2D_{\text{min}} = \sqrt{(3.5 - 4)^2 + (\sqrt{1.5} + 1 - 1)^2}

Dmin=(0.5)2+(1.5)2D_{\text{min}} = \sqrt{(-0.5)^2 + (\sqrt{1.5})^2}

Dmin=0.25+1.5D_{\text{min}} = \sqrt{0.25 + 1.5}

Dmin=1.75D_{\text{min}} = \sqrt{1.75}

Dmin1.32D_{\text{min}} \approx 1.32

Conclusion

The point on the curve y=x2+1y = \sqrt{x - 2} + 1 closest to (4,1)(4, 1) is approximately (3.5,1.5+1)\left(3.5, \sqrt{1.5} + 1\right). The minimum distance between the point (4,1)(4, 1) and the curve is approximately 1.32 units.

Would you like a detailed breakdown of any part, or have any questions?

Related Questions

  1. How do you find the distance between two points in a coordinate plane?
  2. What is the domain of the function y=x2+1y = \sqrt{x - 2} + 1?
  3. How can the derivative test determine the minimum or maximum of a function?
  4. How do you calculate the square root of a non-perfect square manually?
  5. What are other methods for minimizing functions in calculus?

Tip:

Always check the domain of the functions involved in problems to avoid undefined values and incorrect results.

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Math Problem Analysis

Mathematical Concepts

Distance Formula
Minimization in Calculus

Formulas

Distance formula
Quadratic minimization

Theorems

Monotonicity of square root function

Suitable Grade Level

Advanced High School

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