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3 years ago

A = {a, b, c, d}

Mathematics

1 answer:

Helen [10]3 years ago

4 0

Answer:

Johnny is wrong.

$A \cup B = \left\{a,b,c,d,e,f,g,h\right\}$

Step-by-step explanation:

Johnny is wrong.

A better definition would be: $A \cup B$ is the set of all elements that belong to at least one A or B.

So, the elements that belong to both A and B, like c and d in this exercise, also belong to $A \cup B$ .

So:

$A \cup B=\left\{a,b,c,d,e,f,g,h\right\}$

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3 years ago

A plane flying horizontally at an altitude of 1 mi and a speed of 470 mi/h passes directly over a radar station. Find the rate a

kiruha [24]

Answer:

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Step-by-step explanation:

Given:

Speed of plane (s) = 470 mi/h

Height of plane above radar station (h) = 1 mi

Let the distance of plane from station be 'D' at any time 't' and let 'x' be the horizontal distance traveled in time 't' by the plane.

Consider a right angled triangle representing the above scenario.

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Differentiating with respect to time 't', we get:

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Now, plug in all the given values and solve for $\frac{dD}{dt}$ . This gives,

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Therefore, the distance from the plane to the station is increasing at a rate of 407 mi/h.

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