# Find the determinant of $$\begin{vmatrix} sinx & cosx \\ -cosx & sinx \end{vmatrix}$$.

## Solution :

Let | A | = $$\begin{vmatrix} sinx & cosx \\ -cosx & sinx \end{vmatrix}$$

By using 2×2 determinant formula, we obtain

| A | = ( $$sin^2x$$) – ($$-cos^2x$$) = $$sin^2x$$ + $$cos^2x$$ = 1