What is the 13th term of the geometric sequence 4, 12, 36, 108, ...?

Mathematics

1 answer:

bogdanovich [222]2 years ago

7 0

Answer: 2,125,764

Step-by-step explanation:

You can use the equation y=ar^n-1 to find the 13th term where a is the starting term, r is the common ratio, and n is the nth term

The next number is 12/4=3 times greater than the first. So if this sequence is a geometric one, then the next term must be 12*3=36. This is true, and the next term must be 36*3=108, which is also true. Therefore this sequence is a geometric one and its common ratio is 3. Therefore the equation is:

y=4*3^(n-1)

Substitute 13 for n:

y=4*3^(13-1)

y=4*3^12

y=2125764

Therefore, the 13th term of this geometric sequence is 2,125,764

You might be interested in

As.

Natalka [10]

9514 1404 393

Answer:

4/13 h ≈ 0.308 h
22 9/13 km ≈ 22.7 km

Step-by-step explanation:

Mary and Amaruk are starting 35 -15 = 20 km apart. Their closing speed is 40 +25 = 65 km/h. The time it will take to close the gap between them is ...

t = (20 km)/(65 km/h) = 20/65 h = 4/13 h ≈ 0.308 h

They will pass each other after 4/13 hours, about 18 minutes 28 seconds.

In that time, Mary will have increased her distance from Hall Beach by ...

d = (4/13 h)(25 km/h) = 100/13 km = 7 9/13 km

Her distance from Hall Beach when she passes Amaruk will be ...

15 km + 7 9/13 km = 22 9/13 km ≈ 22.7 km . . . . . distance from Hall Beach