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3 years ago

A student runs 100 meters in 11 seconds. What is the speed of the student?

Mathematics

1 answer:

DiKsa [7]3 years ago

7 0

100m= 0.621371 miles

11 seconds = 0.0030556 hours

s=d/t

0.0621371miles/0.0030556hours = 20.3355miles/hours

round off to 20.3 miles per hour

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Xpressions

zlopas [31]

you do parentheses first so 32-8=24
4+2=6

answer 24=6

8 0

2 years ago

Given: cosθ= -4/5 , sin x = -12/13 , θ is in the third quadrant, and x is in the fourth quadrant; evaluate tan 1/2 θ

mrs_skeptik [129]

Answer:

Step-by-step explanation:

If you're looking for what the half angle of the tangent of theta is, I'm a bit confused as to why you think the angle in the 4th quadrant, x, is relevant. But maybe you don't know it isn't and it's a "trick" to throw you off. Hmm...

Anyways, the half angle identity for tangent is

$tan(\frac{\theta}{2})=\frac{sin\theta}{1+cos\theta}$

There are actually 3 identities for the tangent of a half angle, but this one works just as well as either of the others do, so I'm going with this one.

If theta is in QIII, the value of -4 goes along the x axis and the hypotenuse is 5. That makes the missing side, by Pythagorean's Theorem, -3. Filling in our formula:

$tan(\frac{\theta}{2})=\frac{-\frac{3}{5} }{1+(-\frac{4}{5}) }$ which simplifies a bit to

$tan(\frac{\theta}{2})=\frac{-\frac{3}{5} }{\frac{5}{5} -\frac{4}{5} }$ and a bit more to

$tan(\frac{\theta}{2})=\frac{-\frac{3}{5} }{\frac{1}{5} }$

Bring up the lower fraction and flip it to divide to get

$tan(\frac{\theta}{2})=-\frac{3}{5}*\frac{5}{1}$ which of course simplifies to

-3. Choice A.

6 0

3 years ago

Given a sample size n, how will the distribution of the sample mean behave?

Keith_Richards [23]

Answer:
Provided that the sample size, n, is sufficiently large (greater than 30), the distribution of sample means selected from a population will have a normal distribution, according to the Central Limit Theorem.

Explanation:
1. As n increases, the sample mean approaches the population mean
(The Law of Large numbers)
2. The standard error of the sample is
σ/√n
where σ = population standard deviation.
As n increases, the standard error decreases, which means that the error
between the sample and population means decreases.

5 0

2 years ago

Find the exact value of cos (-270).

djyliett [7]

Answer:

Step-by-step explanation:

Assuming this is in degrees, it is actually 0.

8 0

3 years ago

Cassidy's diving platform is 6 ft above the water. One of her dives can

avanturin [10]

Answer:

Before coming back up to the surface the maximum depth, Cassidy went was 6.25 ft. below the water surface

Step-by-step explanation:

The height of Cassidy's diving platform above the water = 6 ft.

The equation that models her dive is d = x² - 7·x + 6

Where;

d = Her vertical position or distance from the water surface

x = Here horizontal distance from the platform

At Cassidy's maximum depth, we have;

dd/dx = d(x² - 7·x + 6)/dx = 2·x - 7 = 0

x = 7/2 = 3.5

∴ At Cassidy's maximum depth, x = 3.5 ft.

The maximum depth, $d_{max}$ = d(3.5) = 3.5² - 7 × 3.5 + 6 = -6.25

The maximum depth, Cassidy went before coming back up to the surface = $d_{max}$ = -6.25 ft = 6.25 ft. below the surface of the water.

8 0

2 years ago