Question

If A is square matrix of order 2 and $|a d j A|=9,$ , find | A |.

If A, B and C are the vertices of a $\Delta A B C$, then what is the value of ${\vec{AB}}+{\vec{BC}}+{\vec{C A}}$ ?

Give an example of vectors $\stackrel{\rightarrow}{a}\$ and $\stackrel{\rightarrow}{b}\$ such that $\vert{\vec{b}}\vert=$ $\vert{\vec{b}}\vert$ but $\stackrel{\rightarrow}{a}\neq \stackrel{\rightarrow}{b}\;.$  

Find the solution of the differential equation ${\frac{d y}{d x}}=x^{3}e^{-2y}$.

Find the matrix A if $\left(\begin{array}{l l l }9 & -1 & 4 \\ -2 & 1 & 3\end{array}\right)$ = A + $\left(\begin{array}{l l l }1 & 2 & -1 \\ 0 & 4 & 9\end{array}\right)$

If $\left(\begin{array}{l l }2x+y & 3y \\ 0 & 4\end{array}\right)$ = $\left(\begin{array}{l l }6 & 0 \\ 0 & 4\end{array}\right)$ then find the value of x.

Find a vector in the direction of $\stackrel{\rightarrow}{a}=\stackrel{\wedge}{i}-2\;\stackrel{\wedge}{j}$ that has magnitude 7 units.