Answer:
- <u>f(t) = -7.561(t + 1.15)(t - 2.53)</u>
Explanation:
The<em> hint </em>is that the function f can be written in the form:
- f(t) = c (t - t₁) (t - t₂)
It is a quadratic function, i.e. a parabola.
The maximum point, maximum height, of a parabola is its vertex.
And the x-coordinate of the vertex is at the midpoint between the two x-intercepts.
The time when the rock reaches the road is one x-intercept: t = 2.53 seconds: (2.53, 0).
The other x-intercept is sucht that (x + 2.53) / 2 = 0.69
- (x + 2.53) / 2 = 0.69
- x + 2.53 = 1.38
- x = 1.38 - 2.53
- x = -1.15
Thus, the equation is:
- f(t) = c(t + 1.15) (t - 2.53).
You can find c by doing t = 0, because at t = 0 the height, f(t), is 22 feet:
- f(0) = 22 = c (0 +1.15)(0 - 2.53)
- 22 = c(1.15)(-2.53)
- 22 = c (-2.9095)
- c = - 22/(2.9095)
- c = - 7.561
Then, the function can be written as:
- f(t) = -7.561(t + 1.15) (t - 2.53) ← answer
54 feet would be exact i think dont take my word for it.
The first factor must be at least 1 and less than 10.
The second factor must be a power of 10.
Move the decimal point to the left until the number is between 1 and 10. Count how many places you move the decimal point.23.6 → 2.36
You moved the decimal point 1 place to the left. The power of 10 is 10 to the power of 1
23.6 = 2.36 × 10 to the power of 1
That trinomial can't be factored. You would have to complete the square to factor it and even then your answer would be an imaginary number.
x² + x + 12 = 0
x² + x = - 12
x² + x + 1/4 = - 12 + 1/4
x² + x + 1/4 = - 11 3/4
x² + x + 1/4 = - 47/4
(x + 1/2)² = - 47/4
x + 1/2 = +/- √(- 47/4)
x + 1/2 = +/-
x = 1/2 +/-
If the constant was a negative, it would be factor-able (is that a word?).
