Questions
If is the inverse of a matrix A, then the sum of all values of for which det(A)+1=0, is
detailed solution
Correct option is C
Given matrix B is the inverse matrix of 3×3 matrix A, Where B=52α1021α3−1We know that ,detA=1detB ∵detA−1=1detASince, det(A) +1=01det(B)+1=0⇒det(B)=−1⇒5(−2−3)−2α(0−α)+1(0−2α)=−1⇒−25+2α2−2α=−1⇒2α2−2α−24=0⇒α2−α−12=0⇒(α−4)(α+3)=0⇒α=−3,4 So, required sum of all values of α is 4−3=1Similar Questions
If [ ] denotes the greatest integer less than or equal to the real number under consideration, and ,, then the value of the determinant is
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