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3 years ago

A monument casts a 40 ft shadow. Adam is 6 ft tall and casts a 5 foot shadow. How tall is the monument

1 answer:

3 0

The answer is 48 feet (D).

Explanation:

To solve this, you must think of the monument and its shadow and Adam and his shadow as a triangle, the person/object being the vertical leg, the shadows being the horizontal leg, and a line connecting them being the hypotenuse. Also, we can assume that these triangles are similar. First, we can set the scale to be 40/5 (the two shadows set a scale because the triangles are similar). Then, we can put x/6 (the actual things are similar, and the scale was established to be building/measurement). Next, we can set the two fractions equal to each other (40/5 = x/6) and solve. We can cross multiply to get 5x = 40 * 6. That goes to 5x = 240. Finally, we can divide by five on each side to get x = 48 feet (D).

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For the inequality, find TWO values for x that make the inequality true: 5x<2

dangina [55]

Answer:

a and c

Step-by-step explanation:

5(-2)<2

-10<2

5(-5)<2

-25<2

7 0

2 years ago

Find the unit tangent vector T and the principal unit normal vector N for the following parameterized curve.

const2013 [10]

Answer:

$T(t) = ( -sin(t^2), cos(t^2) )\\\\N(t) = T'(t) / |T'(t) | = (-cos(t^2) , -sin(t^2))$

$T(t) =r'(t)/|r'(t)| = (2t/ \sqrt{4t^2 + 36} , -6/\sqrt{4t^2 + 36},0)$

$N(t) =T(t)/|T'(t)| = (3/(9 + t^2)^{1/2} , t/(9 + t^2)^{1/2},0)$

Step-by-step explanation:

Remember that for any curve $r(t)$

The tangent vector is given by

$T(t) = \frac{r'(t) }{| r'(t)| }$

And the normal vector is given by

$N(t) = \frac{T'(t)}{|T'(t)|}$

For this case, using the chain rule

$r'(t) = ( -10*2tsin(t^2) , 102t cos(t^2) )\\$

And also remember that

$|r'(t)| = \sqrt{(-10*2tsin(t^2))^2 + ( 10*2t cos(t^2) )^2} \\\\ = \sqrt{400 t^2*( sin(t^2)^2 + cos(t^2) ^2 })\\=\sqrt{400t^2} = 20t$

Therefore

$T(t) = r'(t) / |r'(t) | = ( -10*2tsin(t^2) , 10*2t cos(t^2) )/ 20t\\\\ = ( -10*2tsin(t^2)/ 20t , 10*2t cos(t^2) / 20t )\\= ( -sin(t^2), cos(t^2) )$

Similarly, using the quotient rule and the chain rule

$T'(t) = ( -2t cos(t^2) , -2t sin(t^2))$

And also

$|T'(t)| = \sqrt{ ( -2t cos(t^2))^2 + (-2t sin(t^2))^2} = \sqrt{ 4t^2 ( ( cos(t^2))^2 + ( sin(t^2))^2)} = \sqrt{4t^2} \\ = 2t$

Therefore

$N(t) = T'(t) / |T'(t) | = (-cos(t^2) , -sin(t^2))$

Notice that

1. $|N(t)| = |T(t) | = \sqrt{ cos(t^2)^2 + sin(t^2)^2 } = \sqrt{1} = 1$

2. $N(t)*T(T) = cos(t^2) sin(t^2 ) - cos(t^2) sin(t^2 ) = 0$

Simlarly

$r'(t) = (2t,-6,0) \\$

and

$|r'(t)| = \sqrt{(2t)^2 + 6^2} = \sqrt{4t^2 + 36}$

Therefore

$T(t) =r'(t)/|r'(t)| = (2t/ \sqrt{4t^2 + 36} , -6/\sqrt{4t^2 + 36},0)$

Then

$T'(t) = (9/(9 + t^2)^{3/2} , (3 t)/(9 + t^2)^{3/2},0)$

and also

$|T'(t)| = \sqrt{ ( (9/(9 + t^2)^{3/2} )^2 + ( (3 t)/(9 + t^2)^{3/2})^2 + 0^2 }\\= 3/(t^2 + 9 )$

And since

$N(t) =T(t)/|T'(t)| = (3/(9 + t^2)^{1/2} , t/(9 + t^2)^{1/2},0)$

6 0

2 years ago

The Right Answer Only You will get Reported if its wrong!!!!!

vekshin1

Answer:

Step-by-step explanation:

I found the angle by taking the opposite side of the angle, 38, and dividing it by the hypotenuse, 53.

Then I used the inverse sine function on 38/53 to get the angle 45.81, which I rounded to 46.

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2 years ago

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Which of the following fractions converts to a repeating decimals

Mashutka [201]

Step-by-step explanation:

The answer is a option.

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2 years ago

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The concession stand is selling hot dogs and hamburgers during a game. At

MAVERICK [17]

Answer:

44 hotdogs

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Step-by-step explanation:

b r a i n and p a p e r

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2 years ago