Find the common ratio and an explicit form in each of the following geometric sequences.
1 answer:
Answer:
The explicit form is
Step-by-step explanation:
The explicit form of a geometric sequence is given by:
where an is the nth term, a is the first term of the sequence and r is the common ratio.
In this case:
a=162
The value of the common ratio is obtained by dividing one term by the previous term.
For the first and second terms:
108/162=2/3
For the second and third terms (In order to prove that 2/3 is the common ratio)
72/108=2/3
Therefore:
r=2/3
Replacing a and r in the formula:
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Given :
A boat is being pulled into a dock with a rope attached to the boat at water level. When the boat is 12 feet from the dock, the length of the rope form the boat to the dock is 3 feet longer than twice the height of the dock above the water.
To Find :
The height of the dock.
Solution :
This will make a right angle triangle as given in link below .
Now , applying Pythagoras theorem :
Now , h = 5 or h = -9 .
Now , height cannot be negative .
So , height of the dock is 5 ft .
Hence , this is the required solution .