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            <title>Question 5 Exercise 4.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit04/ex4-1-p3</link>
            <description>Question 5 Exercise 4.1

Solutions of Question 5 of Exercise 4.1 of Unit 04: Sequence and Series. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.

Question 5(i)
$\sum_{j=1}^6(2 j-3)$\begin{align}\sum_{j=1}^6(2 j-3)&amp;=(2.1-3)+(2.2-3)+(2.3-3)+(2.4-3)\\&amp;+(2.5-3)+(2.6-3) \\
\implies \sum_{j=1}^6(2 j-3)&amp;=-1+1+3+5+7+9 .\end{align}$\sum_{k=1}^5(-1)^k 2^{k-1}$\begin{align}\sum_{k=1}^5(-1)^k 2^{k-1}&amp; =(-1)^1 2^{1-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 18:33:10 +0000</pubDate>
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            <title>Question 11 &amp; 12 Exercise 4.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit04/ex4-5-p8</link>
            <description>Question 11 &amp; 12 Exercise 4.5

Solutions of Question 11 &amp; 12 of Exercise 4.5 of Unit 04: Sequence and Series. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$p^{t h}, q^{t h}$$r^{t h}$$a, b, c$$a^{q-r} b^{r-p} c^{p-q}=1$$a_n=a_1 r^{n-1}$$a_p=a_1 r^{p-1}=a \quad a_q=a_1 r^{q-1}=b$$a_r=a_1 r^{r-1}$\begin{align}a^{q-r}&amp;=(a_1 r^{p-1})^{q-r} . \\
b^{r-p}&amp;=(a_1 r^{q-1})^{r-p}, \text { and } \\
c^{p-q}&amp;=(a_1 r^…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 05 Jan 2024 17:30:14 +0000</pubDate>
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