Answer:
not arithmetic
Step-by-step explanation:
An arithmetic sequence has a common difference d between consecutive terms.
Given
= 2n² - 1
Substitute in n = 1, 2, 3, 4 to generate the first 4 terms of the sequence
= 2(1)² - 1 = 2 - 1 = 1
= 2(2)² - 1 = 8 - 1 = 7
= 2(3)² - 1 = 18 - 1 = 17
= 2(4)² - 1 = 32 - 1 = 31
check the difference between consecutive terms
7 - 1 = 6
17 - 7 = 10
31 - 17 = 14
The differences are not common hence not an arithmetic sequence
Answer:
Step-by-step explanation:
To answer this problem, we must bear in mind that the express train travels 3 times faster than the freight train.
If we call F the distance that the freight train travels and we call E at the distance that the express train travels, we must have the distance between them after 15 minutes it must be 30 miles.
So
We also know that:
Since the express train travels 3 times faster than the freight train.
So, like both equations, we have to:
Then miles in the opposite direction.
This is the distance you traveled in 15 minutes.
Therefore, the speed of the express train () is the distance traveled between the time it did