A rock falls off a balcony. It's height (in feet) is given by the formula f(x)=-16t^2+13.4t+120, where t is measured in seconds. How long will it take the rock to hit the ground? Round your answers to the nearest three decimal places.
Answers
Answer:
3.189 seconds
Step-by-step explanation:
You want f(t) = 0, so ...
0 = -16t^2 +13.4t +120
0 = t^2 -0.8375t -7.5 . . . . divide by -16
0 = (t^2 -0.8375t +0.41875^2) -7.5 -0.41875^2 . . . . complete the square*
0 = (t -0.41875)^2 -7.6753515625 . . . . write as a square
√7.6753515625 = t -0.41875 . . . . . . . . add 7.67... and take positive root
t = 0.41875 +√7.6753515625 ≈ 3.189192 . . . . add 0.41875
It will take the rock about 3.189 seconds to hit the ground.
_____
* We complete the square by adding the square of half the coefficient of the linear term (= (-0.8375/2)^2) inside parentheses and subtracting the same amount outside parentheses. This gives a form inside parentheses that is ...
(t^2 -2at +a^2) = (t -a)^2
Completing the square is complicated a little bit by a leading coefficient that is not 1. That is why we divided by -16 first.
_____
Comment on the question
We note that the rock "falls" from the 120 foot high balcony by first traveling upward at a rate of 13.4 feet per second. We also note that the height function is written f(x), but uses t as the variable. That is, it should be f(t) = ...
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100pts: Convert the following expression into postfix notation: 4*(5/2^3-4)+4*(9-2)
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(-1,9)
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Answer:
52 cents
Step-by-step explanation:
Answer:
divide 8 by 4.16
Step-by-step explanation:
symmetry for y=x²+2
Answers
Answer:
x=0
Step-by-step explanation:
The axis of symmetry always passes through the vertex of the parabola . The x -coordinate of the vertex is the equation of the axis of symmetry of the parabola. For a quadratic function in standard form, y=ax2+bx+c , the axis of symmetry is a vertical line x=−b/2a
in our case
y=x^2+2
a=1 b=0 c=2
so x=-b/2a=-0/2*1=0
x=0 is axis of symmetry
275
375
400
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Answers
Answer:
The answer is 400
Step-by-step explanation:
Percent is to 100 as part is to whole.
In this case we have no whole but we have a part, and we have a percentage. 100% is equal to the whole so, 300 divided by 4 is 75 and what you do on the top is what you do on the bottom; 100x4=400
Answers
Answer:
y = (-1/19)(x - 8)² + 1521/76
Step-by-step explanation:
A parabola moves in such a way that it's distance from it's focus and directrix are always equal.
Now, we are given that directrix is y = 9.75 and focus is at (8, 0.25). Focus can be rewritten as (8, ¼) and directrix can be rewritten as y = 39/4
If we consider a point with the coordinates (x, y), it means the distance from this point to the focus is;
√((x - 8)² + (y - ¼)²)
Distance from that point to the directrix is; (y - 39/4)
Thus;
√((x - 8)² + (y - ¼)²) = (y - 39/4)
Taking the square of both sides gives;
((x - 8)² + (y - ¼)²) = (y - 39/4)²
(x - 8)² + y² - ½y + 1/16 = y² - (39/2)y + (39/4)²
Simplifying this gives;
(x - 8)² - (39/4)² = (½ - 39/2)y
(x - 8)² - 1521/4 = -19y
(x - 8)² - 1521/4 = -19y
Divide both sides by -19 to get;
y = (-1/19)(x - 8)² + 1521/76
round.
a) How many strokes above or below par was the team score on the
first round?
Answers
Answer: There are 2 strokes below par that the team has scored in the first round.
Step-by-step explanation:
Since we have given that
Scores of a team
69, 73, 70 and 74
on the first round on a part 72 course.
Now, we need to find the number of strokes above or below the par.
So, we will compare all the scores with 72.
So,
69-72 = -3(below par)
73-72 = 1 (above par)
70-72= - 2 (below par)
74-72 = 2 ( above par)
So, Number of strokes above or below par is given by
Hence, there are 2 strokes below par that the team has scored in the first round.