If $a+b+c=\pi$, then the value of $\left|\begin{array}{ccc}\sin (a+b+c) & \sin (a+c) & \cos b \\ -\sin b & 0 & \tan a \\ \cos (a+c) & \tan (b+c) & 0\end{array}\right|$ is: |
0 1 -1 2 |
0 |
The correct answer is Option (1) - 0 $Δ=\left|\begin{array}{ccc}\sin (a+b+c) & \sin (a+c) & \cos b \\ -\sin b & 0 & \tan a \\ \cos (a+c) & \tan (b+c) & 0\end{array}\right|$ $Δ=\begin{vmatrix}\sin π&\sin(π-b)&\cos b\\=\sin b&0&\tan a\\\cos(π-b)&\tan(π-a)&0\end{vmatrix}$ $Δ=\begin{vmatrix}0&\sin b&\cos b\\-\sin b&0&\tan a\\-\cos b&-\tan b&0\end{vmatrix}$ here it is a skew symmetric matrix so $Δ=0$ |