question_answer

If\[f\left( \frac{-a}{a-1} \right)\], then \[({{a}_{1}}{{b}_{2}}-{{b}_{1}}{{a}_{2}})\,({{b}_{1}}{{c}_{2}}-{{b}_{2}}{{c}_{1}})\]\[={{({{c}_{1}}{{a}_{2}}-{{c}_{2}}{{a}_{1}})}^{2}}.\]\[+\,2ab\,\cos \,(\alpha -\beta )\,\] is equal to

A)  \[{{a}^{2}}+{{b}^{2}}\]     

B)  \[{{a}^{2}}-{{b}^{2}}\]        

C)  \[{{b}^{2}}-{{a}^{2}}\]                   

D)  \[-\,{{a}^{2}}-{{b}^{2}}\]