If A and B are two n times n non-singular matrices, then
Step 1: Understanding non-singular matrices.
A non-singular matrix is a square matrix that has an inverse. The product of two non-singular matrices is always non-singular.
Step 2: Analyzing the product of two matrices.
If both A and B are non-singular matrices, then their product AB is also non-singular. This is because the determinant of AB is the product of the determinants of A and B, and the determinant of a non-singular matrix is non-zero.
Step 3: Exploring other options.
(A) AB is non-singular: Correct. The product of two non-singular matrices is non-singular.
(B) AB is singular: Incorrect. This is not true if both matrices are non-singular.
(C) (AB)^-1 = A^-1 B^-1 : Incorrect. The correct inverse of AB is (AB)^-1 = B^-1 A^-1 , not A^-1 B^-1 .
(D) (AB)^-1 does not exist: Incorrect. The inverse of AB exists, as long as A and B are non-singular.
Step 4: Conclusion.
Thus, the correct answer is (A) AB is non-singular.
Final Answer: AB is non-singular.
Let \[ f(x)=\int \frac{7x^{10}+9x^8}{(1+x^2+2x^9)^2}\,dx \] and $f(1)=\frac14$. Given that 
and $B=\operatorname{adj}(\operatorname{adj}A)$, if $|B|=81$, find the value of $\alpha^2$ (where $\alpha\in\mathbb{R}$).
a times b is equal to