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serious [3.7K]
3 years ago
15

A man starts at a point A and walks 18 feet north. He then turns and walks due east at 18 feet per second. If a searchlight plac

ed at A follows him, at what rate is the light turning 3 seconds after he started walking east
Mathematics
1 answer:
34kurt3 years ago
8 0

Answer:

1/10 per sec

Step-by-step explanation:

When he's walked x feet in the eastward direction, the angle Θ that the search light makes has tangent

tanΘ = x/18

Taking the derivative with respect to time

sec²Θ dΘ/dt = 1/18 dx/dt.

He's walking at a rate of 18 ft/sec, so dx/dt = 18.

After 3seconds,

Speed = distance/time

18ft/sec =distance/3secs

x = 18 ft/sec (3 sec)

= 54ft. At this moment

tanΘ = 54/18

= 3

sec²Θ = 1 + tan²Θ

1 + 3² = 1+9

= 10

So at this moment

10 dΘ/dt = (1/18ft) 18 ft/sec = 1

10dΘ/dt = 1

dΘ/dt = 1/10 per sec

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Find the value of x. <br> View picture for full problem. Please and thank you!<br> m&lt;2 = 6x + 12.
Karo-lina-s [1.5K]

Answer:

x = 8

Step-by-step explanation:

All the sides are equal. So, it is an equilateral triangle. So, all angles are 60 each

6x + 12 = 60

6x = 60 - 12

6x = 48

x = 48/6

x = 8

4 0
2 years ago
Find the area of the shaded region. round answers to the nearest tenth. assume all inscribed polygons are regular. 29.3 units2
FromTheMoon [43]
The picture in the attached figure

we know that
the area of the shaded region is equal to
(2/3)*[area of the circle - the area of the triangle]  

step 1
Find the area of a circle Ac
Ac = π r²
Ac = π (6)²
Ac = 113.10 units²

step 2
find the area of the triangle At
The triangle is an equilateral triangle with angles on each corner equal to 60 degrees. Meanwhile,
the 3 angles at the center is 120 degrees each since a circle is 360 degree.
 We know that the radius (line from centerpoint to corner) is equivalent to 6.
Using the cosine law,
we can calculate for the length of one side.
s² = 6^ + 6² – 2 (6) (6) cos 120
s² = 108
s = 10.4 units
Since this is an equilateral triangle, therefore, all sides are equal.
The area for this is:
At = (sqrt3 / 4) * s²
At = 46.77 units²

step 3
the area of the shaded region=(2/3)*[area of the circle - the area of the triangle]  
the area of the shaded region=(2/3)*[113.10-46.77]------> 44.22 units²

therefore

the answer is
the area of the shaded region is 44.22 units²


5 0
3 years ago
In june 2005 peter mailed a package from his local post office in fayetteville north carolina to a friend in radford virginia fo
erik [133]

0.23w = 2.07

w = 2.07 ÷ 0.23

w = 9 ounces

7 0
3 years ago
50 students live in a dormitory. The parking lot has the capacity for 30 cars. Each student has a car with probability 12 , inde
Maurinko [17]

Answer:

P(X is greater than 30) = 0.06

Step-by-step explanation:

Given that:

Sample proportion (p) = 0.5

Sample size = 30

The Binomial can be approximated to normal with:

\mu = np = 50 \times 0.5 \\ \\ \mu= 25

\sigma = \sqrt{np(1-p) } \\ \\  \sigma = \sqrt{50 \times (0.5)(1-0.5) } \\ \\ \sigma = 3.536

To find:

P(X> 30)

So far we are approximating a discrete Binomial distribution using the continuous normal distribution. 30 lies between 29.5 and 30.5

Normal distribution:

x = 30.5, \mu = 25, \sigma = 3.536

Using the z test statistics;

z = \dfrac{x - \mu}{\sigma}

z = \dfrac{30.5 - 25}{3.536}

z = \dfrac{5.5}{3.536}

z = 1.555

The p-value for P(X>30) = P(Z > 1.555)

The p-value for P(X>30) = 1 - P (Z< 1.555)

From the z tables;

P(X> 30) = 1 - 0.9400

Thus;

P(X is greater than 30) = 0.06

7 0
3 years ago
In functions, what does (x+2)(x-4) equate to? ​
dimaraw [331]

Answer:

f(x) = x^2 -2x -8

Step-by-step explanation:

(x+2)(x-4)

FOIL

first: x*x = x^2

outer: -4x

inner: 2x

last: 2*-4x = -8

Add together

x^2 +2x-4x-8

x^2 -2x -8

This is a parabola

6 0
3 years ago
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