InterviewSolution
Saved Bookmarks
| 1. |
Prove that :`Det[[1+a,1,1],[1,1+b,1],[1,1,1+c]]=abc(1+1/a+1/b+1/c)` |
|
Answer» LHS= `|(1+a, 1,1),(1, 1+b, 1),(1,1,1+c)|` `R_1-> R_1-(1+a)R_3` `R_2-> R_2 - R_3` `|(0,-a,1-(1+c)(1+a)),(0,b,-c),(1,1,1+c)|` `= |(0,-a,-c-a+ac),(0,b,-c),(1,1,1+c)|` expand `c_1` `= 0+0+1|(-a,-c-a+ac),(b,-c)| ` `= ac -[(b)(-c-a-ac)]` `= ac +bc +ba + abc` `= abc(1/b +1/a +1/c+1)` Answer |
|