Surface area of cylinder = 2πrh

Pls help i’ll give brainliest thanks

elixir [45]

Answer: its a

Step-by-step explanation: the only one that makes sense

8 0

2 years ago

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I needs help with it

Slav-nsk [51]

Answer:

a) initial height = 0 m

b) 8 s

c) vertex = (4, 32)

maximum height = 32 m

Step-by-step explanation:

<u>Given equation</u>:

$h=-2t^2+16t$

where:

h is the height of the arrow about the ground (in metres)
t is the time (in seconds)

The initial height of the arrow will be at the beginning of its journey, so when t = 0

Substitute t = 0 into the equation and solve for h:

$\implies h=-2(0)^2+16(0)$

$\implies h=0$

Therefore, the initial height of the arrow is 0 m.

The arrow will hit the ground when the height is 0 m.

Substitute h = 0 into the given equation:

$\implies -2t^2+16t=0$

Factor out -2t:

$\implies -2t(t-8)=0$

Therefore:

$\implies -2t=0 \implies t=0$

And:

$\implies t-8=0 \implies t=8$

Therefore, the arrow will hit the ground at 8 seconds.

The vertex is the <u>turning point</u> of a parabola - it's minimum or maximum point.

As the leading coefficient for the given equation is <u>negative</u>, the parabola <u>opens downwards</u> and so its <u>vertex</u> is its <u>maximum point</u>.

There are different ways to find the vertex of a parabola. The easiest way to find the x-coordinate is by calculating the midpoint of the x-intercepts.

We have determined that the arrow has a height of 0 m at 0 seconds and 8 seconds. Therefore, t = 0 and t = 8 are the x-intercepts. The midpoint is halfway between zero and 8, so the midpoint is t = 4

To find the y-coordinate, substitute t = 4 into the equation and solve for h:

$\implies h=-2(4)^2+16(4)$

$\implies h=-32+64$

$\implies h=32$

Therefore, the coordinates of the vertex are (4, 32)

The maximum height is the y-coordinate of the vertex.

Therefore, the maximum height is 32 m

6 0

1 year ago

Which numbers are rational? The dots, . . . , indicate that the pattern continues. I. 9.9999999 . . . II. 9.234 III. 9.909909

tia_tia [17]

9.234, because it ends.

3 0

3 years ago

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8. f(x) = x² + 3x - 2.

Ivahew [28]

Answer:

(a) x² − 13x + 4

(b) x² − 26x + 153

Step-by-step explanation:

f(x) = x² + 3x − 2

a + ß = -3

aß = -2

(a) (x − a²) (x − ß²)

x² − (a² + ß²) x + a²ß²

x² − ((a + ß)² − 2aß) x + a²ß²

x² − ((-3)² − 2(-2)) x + (-2)²

x² − (9 + 4) x + 4

x² − 13x + 4

(b) (x − (a − ß)²) (x − (a + ß)²)

x² − ((a − ß)² + (a + ß)²) x + (a − ß)²(a + ß)²

x² − (a² − 2aß + ß² + a² + 2aß + ß²) x + (a² − 2aß + ß²)(a + ß)²

x² − (2a² + 2ß²) x + (a² − 2aß + ß²)(a + ß)²

x² − 2(a² + ß²) x + (a² − 2aß + ß²)(a + ß)²

x² − 2((a + ß)² − 2aß) x + ((a + ß)² − 4aß)(a + ß)²

x² − 2((-3)² − 2(-2)) x + ((-3)² − 4(-2))(-3)²

x² − 2(9 + 4) x + (9 + 8)(9)

x² − 26x + 153

5 0

3 years ago

Yolanda is saving money to buy a game. so far she has saved $30 , which is five-sixths of the total cost of the game. how much d

inna [77]

A trick is to replace the "of" with a multiplication symbol"
the 30 dollar is (5/6 of the total cost =>30=(5/6)*c =>c=30*(6/5)=36
the game cost 36 dollars

4 0

3 years ago