Most Important Selected Qs for JEE AdvancedMathematicsVector Algebra

Given A =2 i +3 j +6 k , B = i + j -2 k and C = i +2 j + k . Compute the value of | A ( A ( A B )) C | .

Correct answer

343

Step-by-step solution

aligned & V = A (( A ~B ) A -( A ~A ) B ) C & =( A ( A ~B ) A _ zero -( A ~A ) A B ) C & =-| A |^2 [ array lll A & ~B & C array ] aligned Now, | A |^2=4+9+36=49 aligned & [ array lll A & ~B & C array ]= | array ccc 2 & 3 & 6 1 & 1 & -2 1 & 2 & 1 array |=2(1+4)-1(3-12)+1(-6-6) & =10+9-12=7 & |-| A |^2[ ~A ~B C ] |=49 7=343 aligned

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