નિશ્ચાયકના ગુણધર્મનો ઉપયોગ કરી  સાબિત કરો કે, $\left| {\begin{array}{*{20}{l}}
  {\sin \alpha }&{\cos \alpha }&{\cos (\alpha  + \delta )} \\ 
  {\sin \beta }&{\cos \beta }&{\cos (\beta  + \delta )} \\ 
  {\sin \gamma }&{\cos \gamma }&{\cos (\gamma  + \delta )} 
\end{array}} \right| = 0$

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$\Delta=\left|\begin{array}{lll}\sin \alpha & \cos \alpha & \cos (\alpha+\delta) \\ \sin \beta & \cos \beta & \cos (\beta+\delta) \\ \sin \gamma & \cos \gamma & \cos (\gamma+\delta)\end{array}\right|$

$=\frac{1}{\sin \delta \cos \delta}\left|\begin{array}{ccc}\sin \alpha \sin \delta & \cos \alpha \cos \delta & \cos \alpha \cos \delta-\sin \alpha \sin \delta \\ \sin \beta \sin \delta & \cos \beta \cos \delta & \cos \beta \cos \delta-\sin \beta \sin \delta \\ \sin \gamma \sin \delta & \cos \gamma \cos \delta & \cos \gamma \cos \delta-\sin \gamma \sin \delta\end{array}\right|$

Applying $C_{1} \rightarrow+C_{1}+C_{3},$ we have:

$\Delta=\frac{1}{\sin \delta \cos \delta}\left|\begin{array}{lll}
\cos \alpha \cos \delta & \cos \alpha \cos \delta & \cos \alpha \cos \delta-\sin \alpha \sin \delta \\
\cos \beta \cos \delta & \cos \beta \cos \delta & \cos \beta \cos \delta-\sin \beta \sin \delta \\
\cos \gamma \cos \delta & \cos \gamma \cos \delta & \cos \gamma \cos \delta-\sin \gamma \sin \delta
\end{array}\right|$

Here, two columns $C_{1}$ and $C_{2}$ are identical.

$\therefore \Delta=0$

Hence, the given result is proved.

Similar Questions

$\left|\begin{array}{ccc}\cos \alpha \cos \beta & \cos \alpha \operatorname{csin} \beta & -\sin \alpha \\ -\sin \beta & \cos \beta & 0 \\ \sin \alpha \cos \beta & \sin \alpha \sin \beta & \cos \alpha\end{array}\right|$ નું મૂલ્ય શોધો.

નિશ્ચાયકના ગુણધર્મનો ઉપયોગ કરી  સાબિત કરો કે, $\left|\begin{array}{ccc}\alpha & \alpha^{2} & \beta+\gamma \\ \beta & \beta^{2} & \gamma+\alpha \\ \gamma & \gamma^{2} & \alpha+\beta\end{array}\right|=(\beta-\gamma)(\gamma-\alpha)(\alpha-\beta)(\alpha+\beta+\gamma)$

 $\left| {\begin{array}{*{20}{c}}
  {{{(b + c)}^2}}&{{a^2}}&{{a^2}} \\ 
  {{b^2}}&{{{(a + c)}^2}}&{{b^2}} \\ 
  {{c^2}}&{{c^2}}&{{{(a + b)}^2}} 
\end{array}} \right|$ ની કિમત મેળવો.

નીચે આપેલ શ્રેણિક પૈકી ક્યો શ્રેણિક એ શ્રેણિક $\left[\begin{array}{cc}-1 & 2 \\ 1 & -1\end{array}\right]$ પર એક્જ હાર પ્રક્રિયાથી મેળવી શકાય નહીં.

  • [JEE MAIN 2022]

નિશ્ચાયકના ગુણધર્મનો ઉપયોગ કરીને સાબિત કરો : $\left|\begin{array}{ccc}a^{2}+1 & a b & a c \\ a b & b^{2}+1 & b c \\ c a & c b & c^{2}+1\end{array}\right|=1+a^{2}+b^{2}+c^{2}$