Please help with my college algebra questions. Even 1 question would help. Thank you!~
A harmless rocket is filled with water and then pressurized using a handheld pump. The rocket is then release and off it goes! If the rocket has an initial velocity of 96 ft/sec, the height of the rocket can be modeled by the function: h(t)=-16t^2 +96t where h(t) represents the height of the rocket after t sec.
1)What is the rocket’s height at t=1 sec?
2)What is the rocket’s height at t=3 sec?
3)What is the average rate of change on the parabola from x=[1,3] ?
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Consider the parabolic function:
r(x)= -2x^2 -3x +5 Let r(x) =0
4) Solve by factoring.
5)Solve by using the quadratic formula.
6)Solve by completing the square.
7)What is the vertex?
Thank you!!!!!!!!!
I think you have to differentiate with respect to t, which gives
h = 32*t +96
Then substitute t=1 to give h=128.
its been a long time since I did this kinda stuff, please let someone else confirm it.
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1. h(1) = -16(1)² + 96(1) = 80m
2. h(3) = -16(3)² + 96(3) = 144m
3. The average rate of change is the mean value of the derivative. This is given by ∫[a to b] f’(x) dx / (b – a). The integral of the derivative is just the original function so these are the values we have already calculated.
(144 – 80) / (3 – 1)
64 / 2
32
4. -2x² – 3x +5 = 0
2x² + 3x – 5 = 0
(2x + 5)(x – 1) = 0
2x + 5 = 0 OR x – 1 = 0
x = -5 / 2 OR x = 1
5. ax² + bx + c = 0
-2x² – 3x + 5 = 0
a = -2, b = -3, c = 5
x = [-b ± √(b² - 4ac)] / 2a
x = [3 ± √[(-3)² - 4(-2)(5)]] / 2(-2)
x = [3 ± √49] / -4
x = (3 ± 7) / -4
x = (3 + 7) / -4 OR (3 – 7) / -4
x = 5 / 2 OR x = 1
6. -2x² – 3x + 5 = 0
2x² + 3x – 5 = 0
2(x² + 3x / 2) – 5 = 0
2[(x + 3 / 4)² - 9 / 16] – 5 = 0
2(x + 3 / 4)² – 9 / 8 – 5 = 0
2(x + 3 / 4)² – 9 / 8 – 40 / 8 = 0
2(x + 3 / 4)² – 49 / 8 = 0
2(x + 3 / 4)² = 49 / 8
(x + 3 / 4)² = 49 / 16
x + 3 / 4 = ±√(49 / 16)
x + 3 / 4 = ±(√49 / √16)
x + 3 / 4 = ±(7 / 4)
x = 7 / 4 – 3 / 4 OR -7 / 4 – 3 / 4
x = 4 / 4 OR -10 / 4
x = 1 OR x = 5 / 2
7. -2x² – 3x + 5 = 0
-2(x² + 3x / 2) + 5 = 0
-2[(x + 3 / 4)² - 9 / 16] + 5 = 0
-2(x + 3 / 4)² + 9 / 8 + 5 = 0
-2(x + 3 / 4)² + 9 / 8 + 40 / 8 = 0
-2(x + 3 / 4)² + 49 / 8 = 0
The vertex is a maximum at (-3 / 4, 49 /
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