Answer:
13 ft/s
Step-by-step explanation:
t seconds after the boy passes under the balloon the distance between them is ...
d = √((15t)² +(45+5t)²) = √(250t² +450t +2025)
The rate of change of d with respect to t is ...
dd/dt = (500t +450)/(2√(250t² +450t +2025)) = (50t +45)/√(10t² +18t +81)
At t=3, this derivative evaluates to ...
dd/dt = (50·3 +45)/√(90+54+81) = 195/15 = 13
The distance between the boy and the balloon is increasing at the rate of 13 ft per second.
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The boy is moving horizontally at 15 ft/s, so his position relative to the spot under the balloon is 15t feet after t seconds.
The balloon starts at 45 feet above the boy and is moving upward at 5 ft/s, so its vertical distance from the spot under the balloon is 45+5t feet after t seconds.
The straight-line distance between the boy and the balloon is found as the hypotenuse of a right triangle with legs 15t and (45+5t). Using the Pythagorean theorem, that distance is ...
d = √((15t)² + (45+5t)²)
Line 1 and line 4 are parallel
Step-by-step explanation:
Two lines are said to be parallel if they have same slope.
In order to compare the lines given, we have to write them all in the same form, and then compare their slopes.
Line 1:
Applying distributive property,
Line 2:
Line 3:
Applying distributive property,
Line 4:
re-arranging,
Now we have rewritten all the lines in the form 
, where m is the slope. By comparing the values of m, we see:
Therefore, the lines which are parallel are line 1 and line 4.
Learn more about parallel and perpendicular lines:
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Answer:
-9
Step-by-step explanation:
The triangle inequality requires the third side be in the range
.. 12 -4 ≤ third side ≤ 12 +4
.. 8 ≤ third side ≤ 16 . . . . . . . . . your answer is the number(s) in this range
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Some define the triangle inequality using < rather than ≤. Be careful here.
Answer:
12 the answer
Step-by-step explanation:
