JEE Main 2015 · 10 Apr · Shift 1 · Mathematics Q65

MathematicsSingle correct+4 / -1Question 65 of 90

If $A=\begin{bmatrix}0&-1\\1&0\end{bmatrix}$ , then which one of the following statements is not correct ?

A^4-I=A^2+I

A^3-I=A(A-I)

A^2+I=A(A^2-I)

A^3+I=A(A^3-I)

Answer and worked solution

Official answer: C

$A^2=-I$ , $A^3=-A$ and $A^4=I$ . Check each:

So (3) is not correct.

JEE Main 2015 · 10 Apr · Shift 1, Mathematics question 65