Practicing Success
Practicing Success
CUET Preparation Today
The value of the determinant $Δ=\begin{vmatrix}\cos (α+β)&- \sin (α+β)& \cos 2β\\\sin α&\cos α&\sin β\\-\cos α&\sin α&-\cos β\end{vmatrix}$, is |
$\cos^2 α$ $\sin^2 α$ $\sin(α-β)$ 0 |
0 |
Applying $R_1 → R_1 + (\sin β) R_2 + (\cos βB) R_3$, we get $Δ=\begin{vmatrix}0&0&0\\\sin α&\cos α&\sin β\\-\cos α&\sin α&-\cos β\end{vmatrix}=0$ |
