Among the statements :
(S1) : $2023^{2022}-1999^{2022}$ is divisible by 8
(S2) : $13(13)^{n}-12 n-13$ is divisible by 144 for infinitely many $n \in \mathbb{N}$
Solution
We have, $S_1$ : $(2023)^{2022}-(1999)^{2022}$
<br/><br/>$$
\begin{aligned}
& =(1999+24)^{2022}-(1999)^{2022}={ }^{2022} C_0(1999)^{2022}(24)^0 \\\\
& +{ }^{2022} C_1(1999)^{2021}(24)^1+{ }^{2022} C_2(1999)^{2020}(24)^2 \\\\
& +\ldots-(1999)^{2022} \\\\
& ={ }^{2022} C_1(1999)^{2021}(24)+{ }^{2022} C_2(1999)^{2022}(24)^2 \\\\
& =24\left({ }^{2022} C_1(1999)^{2021}+{ }^{2022} C_2(1999)^{2022}(24)+\ldots+\ldots\right) \\\\
& \Rightarrow S_1 \text { is divisible by } 24
\end{aligned}
$$
<br/><br/>$$
\begin{aligned}
& \text { Now, } S_2: 13(13)^n-12 n-13 \\\\
& \text { Here, } 13^n=(1+12)^n \\\\
& \quad=1+{ }^n C_1 12+{ }^n C_2(12)^2+{ }^n C_3(12)^3 \\\\
& \begin{aligned}
\therefore S_2: & 13\left(1+{ }^n C_1(12)+{ }^n C_2(12)^2+{ }^n C_3(12)^3+\ldots\right)-12 n-13 \\\\
\quad= & 13+156 n+13\left({ }^n C_2(12)^2+{ }^n C_3(12)^3+\ldots\right)-12 n-13 \\\\
\quad= & 144 \times 13\left({ }^n C_2+{ }^n C_3(12)+\ldots\right)
\end{aligned}
\end{aligned}
$$
<br/><br/>$\Rightarrow S_2$ is divisible by 144 for infinitely many $n \in N$
About this question
Subject: Mathematics · Chapter: Binomial Theorem · Topic: Binomial Expansion
This question is part of PrepWiser's free JEE Main question bank. 193 more solved questions on Binomial Theorem are available — start with the harder ones if your accuracy is >70%.