1.

Without expanding, show that the value of each of the following determinants is zero :\(\begin{vmatrix}2& 3 & 7 \\[0.3em]13& 17 &5 \\[0.3em]15 &20 & 12\end{vmatrix}\)

Answer»

Let Δ = \(\begin{vmatrix}2& 3 & 7 \\[0.3em]13& 17 &5 \\[0.3em]15 &20 & 12\end{vmatrix}\) 

Applying C3 → C3 – C2, gives

⇒ Δ = \(\begin{vmatrix}2& 3 & 7 \\[0.3em]13& 17 &5 \\[0.3em]2 &3 & 7\end{vmatrix}\) 

As, 

R1 = R3

So value so determinant is zero.



Discussion

No Comment Found