Problem

Given the matrix A=[121 242 121], find the nullity of A.

Answer

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Answer

Step 3: Solving this system, we see that the system is dependent and the solution is a line in R3, which is a one-dimensional space. Therefore, the nullity of A is 1.

Steps

Step 1 :Step 1: The nullity of a matrix is the dimension of the null space of the matrix. The null space of a matrix A is the set of all vectors x such that Ax=0.

Step 2 :Step 2: To find the null space of the matrix, we solve the system Ax=0. In this case, this gives us the system [121 242 121][x1 x2 x3]=0, which simplifies to x1+2x2x3=0,2x1+4x22x3=0,x12x2+x3=0.

Step 3 :Step 3: Solving this system, we see that the system is dependent and the solution is a line in R3, which is a one-dimensional space. Therefore, the nullity of A is 1.

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