Math Problem Statement

Given A (-2, -4), B(4,6), if curve AB is continuous, y(k)=3, k=?

Solution

The problem provides two points, A(2,4)A(-2, -4) and B(4,6)B(4, 6), and asks for the value of kk such that the point (k,3)(k, 3) lies on the continuous curve AB.

Assuming that the curve is a straight line between points A and B (since no other information about the curve is provided), we can find the equation of the line passing through points A and B. After that, we can substitute y(k)=3y(k) = 3 to find the corresponding kk-value.

Step 1: Find the slope of the line

The slope of a line through two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is given by:

m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}

For points A(2,4)A(-2, -4) and B(4,6)B(4, 6):

m=6(4)4(2)=6+44+2=106=53m = \frac{6 - (-4)}{4 - (-2)} = \frac{6 + 4}{4 + 2} = \frac{10}{6} = \frac{5}{3}

Step 2: Equation of the line

Using the point-slope form of the equation of a line, which is:

yy1=m(xx1)y - y_1 = m(x - x_1)

Substitute m=53m = \frac{5}{3} and point A(2,4)A(-2, -4):

y(4)=53(x(2))y - (-4) = \frac{5}{3}(x - (-2)) y+4=53(x+2)y + 4 = \frac{5}{3}(x + 2)

Simplify:

y+4=53x+103y + 4 = \frac{5}{3}x + \frac{10}{3} y=53x+1034y = \frac{5}{3}x + \frac{10}{3} - 4 y=53x123y = \frac{5}{3}x - \frac{12}{3} y=53x4y = \frac{5}{3}x - 4

Step 3: Find kk such that y(k)=3y(k) = 3

Substitute y=3y = 3 into the equation:

3=53k43 = \frac{5}{3}k - 4

Now, solve for kk:

3+4=53k3 + 4 = \frac{5}{3}k 7=53k7 = \frac{5}{3}k k=7×35=215k = \frac{7 \times 3}{5} = \frac{21}{5}

Thus, k=215k = \frac{21}{5} or 4.2.

Final Answer:

The value of kk is 215\frac{21}{5} or approximately 4.2.

Would you like more details, or do you have any questions?

Here are 5 related questions for further exploration:

  1. How would the process change if the curve between A and B was not a straight line?
  2. What is the importance of the slope in determining the equation of a line?
  3. How do you find the distance between two points in a plane?
  4. Can you express the equation of the line in standard form?
  5. How would the answer change if y(k)y(k) were a different value?

Tip: Always check your line equation by substituting the original points to confirm it's correct!

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Linear Equations

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Equation of a line: y - y1 = m(x - x1)

Theorems

Slope-intercept form of a line

Suitable Grade Level

Grades 9-11