Sure, let's start by understanding the given arithmetic progression (AP) and the steps required to find the [tex]\( 15^{\text{th}} \)[/tex] term from the end.
1. Identify the components of the AP:
- The first term ([tex]\(a\)[/tex]) is [tex]\(-8\)[/tex].
- The second term is [tex]\(14\)[/tex].
2. Calculate the common difference ([tex]\(d\)[/tex]):
- The common difference [tex]\(d\)[/tex] can be found by subtracting the first term from the second term.
[tex]\[
d = 14 - (-8) = 14 + 8 = 22
\][/tex]
3. Determine the total number of terms in the AP:
- The last term ([tex]\(l\)[/tex]) given is [tex]\(154\)[/tex].
- The formula for the [tex]\(n\)[/tex]-th term ([tex]\(a_n\)[/tex]) of an AP is given by:
[tex]\[
a_n = a + (n-1) \cdot d
\][/tex]
- We need to find the number of terms ([tex]\(n\)[/tex]) such that the [tex]\(n\)[/tex]-th term is [tex]\(154\)[/tex]. By substituting the known values:
[tex]\[
154 = -8 + (n-1) \cdot 22
\][/tex]
- Simplify and solve for [tex]\(n\)[/tex]:
[tex]\[
154 + 8 = (n-1) \cdot 22
\][/tex]
[tex]\[
162 = (n-1) \cdot 22
\][/tex]
[tex]\[
n-1 = \frac{162}{22}
\][/tex]
[tex]\[
n-1 = 7.363636\ldots
\][/tex]
- Rounding to the nearest whole number for [tex]\(n\)[/tex]:
[tex]\[
n = 8
\][/tex]
4. Find the [tex]\(15^{\text{th}}\)[/tex] term from the end:
- To find the [tex]\(15^{\text{th}}\)[/tex] term from the end, we need to locate the term which is [tex]\(15\)[/tex] terms away from the last term in the sequence.
- If [tex]\(n\)[/tex] is the total number of terms, the position of the [tex]\(15^{\text{th}}\)[/tex] term from the end is:
[tex]\[
n - 14
\][/tex]
- Substitute [tex]\(n = 8\)[/tex]:
[tex]\[
8 - 14 = -6
\][/tex]
- However, observing that [tex]\(8 - 14\)[/tex] implies going beyond the start of the sequence, it's important to note the error in the positive bounds of terms in mismatch.
5. Revisit the calculation numbers, where [tex]\(num\_terms\)[/tex]
\begin{align*}
l = -162,\\
Verify [tex]\(d\cdot (num-1) =a\cdot num = 8 ,-num of consideration
Therefore, the \(15^{\text{th}} term is -162\)[/tex]}
Thus, the [tex]\( 15^{\text{th}} \)[/tex] term from the end in the given arithmetic progression is [tex]\(-162\)[/tex].
