1. **State the problem:** We have a parabolic arch represented by the polynomial $$p(x) = -0.0025x^2 - 0.025x + 136$$.
(i) Write the coordinates of point A (the highest point on the parabola).
(ii) Find the span of the arch (distance between points Q and P where the parabola intersects the x-axis).
(iii) (b) Find the values of $$p(x)$$ at $$x=100$$ and $$x=-100$$ and check if they are the same.
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2. **Find point A (vertex of the parabola):**
The vertex of a parabola $$y = ax^2 + bx + c$$ is at $$x = -\frac{b}{2a}$$.
Here, $$a = -0.0025$$ and $$b = -0.025$$.
Calculate:
$$x_A = -\frac{-0.025}{2 \times -0.0025} = -\frac{-0.025}{-0.005} = -5$$
Now find $$p(-5)$$:
$$p(-5) = -0.0025(-5)^2 - 0.025(-5) + 136 = -0.0025(25) + 0.125 + 136 = -0.0625 + 0.125 + 136 = 136.0625$$
So, point A is $$(-5, 136.0625)$$.
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3. **Find the span of the arch:**
The span is the distance between points Q and P on the x-axis.
Given:
$$Q = (-238.5, 0)$$
$$P = (228.5, 0)$$
Span = $$228.5 - (-238.5) = 228.5 + 238.5 = 467$$
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4. **Find $$p(100)$$ and $$p(-100)$$:**
Calculate $$p(100)$$:
$$p(100) = -0.0025(100)^2 - 0.025(100) + 136 = -0.0025(10000) - 2.5 + 136 = -25 - 2.5 + 136 = 108.5$$
Calculate $$p(-100)$$:
$$p(-100) = -0.0025(-100)^2 - 0.025(-100) + 136 = -0.0025(10000) + 2.5 + 136 = -25 + 2.5 + 136 = 113.5$$
Since $$p(100) = 108.5$$ and $$p(-100) = 113.5$$, they are not the same.
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**Final answers:**
(i) Point A coordinates: $$(-5, 136.0625)$$
(ii) Span of the arch: $$467$$ units
(iii) (b) $$p(100) = 108.5$$ and $$p(-100) = 113.5$$, so values are not the same.
Parabolic Arch 97Cb7C
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