99.6k views
5 votes
Someone please help I dont understand

Someone please help I dont understand-example-1
User Wonde
by
6.7k points

2 Answers

6 votes

The series -13, -7, -1, 5, 11 follows a pattern of adding 6 to each term successively. The representation that fits this progression is: -13 + 6K, where K denotes the term's position.

The given series is:

-13 + (-7) + (-1) + 5 + 11

This series forms a sequence by adding 6 to each consecutive term.

To represent this sequence in terms of an equation or expression, we can use a general formula:


\[ a_n = a_1 + (n - 1) \cdot d \]

Where:


\(a_n\) represents the nth term in the sequence.


\(a_1\) is the first term.


\(n\) is the term number.


\(d\) is the common difference between terms.

For this series, the first term
(\(a_1\)) is -13, and the common difference
(\(d\))is 6.

Let's find the 5th term in the sequence (as given series contains 5 terms):


\[ a_5 = a_1 + (5 - 1) \cdot d \]


\[ a_5 = -13 + 4 \cdot 6 \]


\[ a_5 = -13 + 24 \]


\[ a_5 = 11 \]

The 5th term of the sequence is indeed 11, confirming that the pattern of adding 6 to each consecutive term holds true. Therefore, the correct representation corresponding to this series is: -13 + 6K, where
\(K\)represents the position of the term in the sequence.

User Ishan Fernando
by
8.1k points
0 votes

The answer is
\sum_(k=1)^(5)-13+6k . The last option is correct.

This is because we can see from the image that the series is arithmetic with a common difference of 6. The first term of the series is −13 and there are 5 terms in the series.

Therefore, the sum of the series is given by
\sum_(k=1)^(5)-13+6k

We can also see from the image that the series is equal to the sum of the following two series:

= -13+(-7)+(-1)+5+11 &= -13+(-7)+(-1)+(5+11)


= -13+(-7)+(-1)+16


= \sum_(k=1)^(3)-13+6k

and

= -13+(-7)+(-1)+5+11

= (-13+5)+(11-7)+(-1)

= -8+4+(-1)

= -5


= \sum_(k=1)^(1)-19+6k

Therefore, the sum of the series is given by


-13+(-7)+(-1)+5+11 &= \sum_(k=1)^(3)-13+6k + \sum_(k=1)^(1)-19+6k


= \sum_(k=1)^(5)-13+6k

Last option is correct.

User Bill Healey
by
7.3k points