Given u = 3i − 8j and v = −4i + 8j, what is u • v? 73 8 −76 −56

Mathematics

1 answer:

Ivan2 years ago

4 0

<h3>Answer: -76 (choice C)</h3>

Explanation:

We're applying the dot product.

u dot v = 3*(-4) + (-8)*8

u dot v = -12 - 64

u dot v = -76

The idea is that we multiply the x coordinates together, and the y coordinates together separately. Afterward you add the products. The result of any dot product is a scalar value, aka a single number.

The dot product is useful in many applications. One of which is to determine if two vectors are orthogonal.

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derek used a total of 4 pounds of grape, roma, and plum tomatoes including 2 pounds of grape tomatoes and 14 ounces of roma toma

Ilya [14]

He used 18 ounces.
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Convert pounds to ounces. Since there are 16 ounces in a pound, he has a total of 64 ounces.
Two pounds of grape tomatoes = 32 ounces
The roma tomatoes are 14 ounces.
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64 - 46 = 18 .... Total - (Grape + Roma) = Plum

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3 years ago

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If f (x)=2(x)2 +5/(x+2), complete the following statement (round your answer to the nearest hundredth): FO) = Answer here

kari74 [83]

Answer:

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Step-by-step explanation:

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3 years ago

Ex 7) Imagine a mile-long bar of metal such as the rail along railroad tracks. Suppose that the rail is anchored on both ends an

Fantom [35]

9514 1404 393

Answer:

about 44.5 feet

Step-by-step explanation:

We can write relations for the height of the rail as a function of initial length and expanded length, but the solution cannot be found algebraically. A graphical solution or iterative solution is possible.

Referring to the figure in the second attachment, we can write a relation between the angle value α and the height of the circular arc as ...

h = c·tan(α) . . . . . . where c = half the initial rail length

Then the length of the expanded rail is ...

s = r(2α) = (c/sin(2α)(2α) . . . . . . where s = half the expanded rail length

Rearranging this last equation, we have ...

sin(2α)/(2α) = c/s

It is this equation that must be solved iteratively. We find the solution to be ...

α ≈ 0.0168538794049 radians

So, the height of the circular arc is ...

h = 2640.5·tan(0.0168538794049) ≈ 44.4984550191 . . . feet

The rail will bow upward by about 44.5 feet.

_____

<em>Additional comments</em>

Note that s and c in the diagram are half the lengths of the arc and the chord, respectively. The ratio of half-lengths is the same as the ratio of full lengths: c/s = 2640/2640.5 = 5280/5281.

We don't know the precise shape the arc will take, but we suspect is is not a circular arc. It seems likely to be a catenary, or something similar.

We used Newton's method iteration to refine the estimate of the angle from that shown on the graph. The iterator used is x' = x -f(x)/f'(x), where x' is the next guess based on the previous guess of x. Only a few iterations are required obtain an angle value to full calculator precision.