Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

If $A=\begin{bmatrix}1 & 0\\\frac{1}{25} & 1\end{bmatrix}$, then the value of $A^{125}$ is :

Options:

$\begin{bmatrix}1 & 5\\0 & 1\end{bmatrix}$

$\begin{bmatrix}0 & 1\\1 & 5\end{bmatrix}$

$\begin{bmatrix}1 & 0\\5 & 1\end{bmatrix}$

$\begin{bmatrix}5 & 1\\1 & 0\end{bmatrix}$

Correct Answer:

$\begin{bmatrix}1 & 0\\5 & 1\end{bmatrix}$

Explanation:

The correct answer is Option (3) → $\begin{bmatrix}1 & 0\\5 & 1\end{bmatrix}$

$A=\begin{bmatrix}1 & 0\\\frac{1}{25} & 1\end{bmatrix}$

$A^2=\begin{bmatrix}1 & 0\\\frac{2}{25} & 1\end{bmatrix}$

$A^3=\begin{bmatrix}1 & 0\\\frac{3}{25} & 1\end{bmatrix}$

so $A^n=\begin{bmatrix}1 & 0\\\frac{n}{25} & 1\end{bmatrix}⇒A^{125}\begin{bmatrix}1 & 0\\\frac{125}{25} & 1\end{bmatrix}$

$A^{125}\begin{bmatrix}1 & 0\\5& 1\end{bmatrix}$