Answer:
The correct answer
Explanation:
To design a path for Tony Hawk from point T(-4,0) to the halfpipe at P(14,18) while avoiding the garbage cans at points A(-3,1), B(8,6), C(0,5), D(4,14), E(14,13), F(11,15), and G(3,7), we can use a combination of linear and quadratic relations.
1) Path description:
- Segment 1: Linear equation from T to A(B):
Line equation: y = mx + b
Calculate slope (m) = (y2 - y1) / (x2 - x1) = (1 - 0) / (-3 - (-4)) = 1
Calculate y-intercept (b): substitute the coordinates of point T
0 = 1*(-4) + b
b = 4
Line equation: y = x + 4
- Segment 2: Quadratic equation that opens up from A to C:
Parabola equation in vertex form: y = a(x - h)^2 + k
Find the vertex by taking the average of the x-coordinates of points A and C:
h = (x1 + x2) / 2 = (-3 + 0) / 2 = -3/2
Substitute the coordinates of A or C to find k:
1 = a(-3 - (-3/2))^2 + k
1 = a(0.5)^2 + k
1 = 0.25a + k
Choose a stretch factor (a) of 4 (for example)
Substitute k = 1 - 0.25a = 1 - 0.25(4) = 1 - 1 = 0
Parabola equation: y = 4(x + 3/2)^2
- Segment 3: Linear equation from C to D:
Line equation: y = mx + b
Calculate slope (m) = (y2 - y1) / (x2 - x1) = (14 - 5) / (4 - 0) = 9/4
Calculate y-intercept (b): substitute the coordinates of point D
14 = (9/4)(4) + b
14 = 9 + b
b = 14 - 9 = 5
Line equation: y = (9/4)x + 5
- Segment 4: Quadratic equation that opens down from D to F:
Parabola equation in vertex form: y = a(x - h)^2 + k
Find the vertex by taking the average of the x-coordinates of points D and F:
h = (x1 + x2) / 2 = (4 + 11) / 2 = 15/2
Substitute the coordinates of D or F to find k:
14 = a(4 - 15/2)^2 + k
14 = a(-7/2)^2 + k
14 = 49/4a + k
Choose a stretch factor (a) of -2 (for example)
Substitute k = 14 - 49/4a = 14 - 49/4(-2) = 14 + 49/2 = 14 + 24.5 = 38.5
Parabola equation: y = -2(x - 15/2)^2 + 38.5
- Segment 5: Linear equation from F to P:
Line equation: y = mx + b
Calculate slope (m) = (y2 - y1) / (x2 - x1) = (18 - 15) / (14 - 11) = 1
Calculate y-intercept (b): substitute the coordinates of point F
15 = 1(11) + b
b = 15 - 11 = 4
Line equation: y = x + 4
2) Equations for each segment:
- Segment 1: Linear equation from T to A(B):
Line equation: y = x + 4
- Segment 2: Quadratic equation that opens up from A to C:
Parabola equation: y = 4(x + 3/2)^2
- Segment 3: Linear equation from C to D:
Line equation: y = (9/4)x + 5
- Segment 4: Quadratic equation that opens down from D to F:
Parabola equation: y = -2(x - 15/2)^2 + 38.5
- Segment 5: Linear equation from F to P:
Line equation: y = x +