Class 12 Matrices · Mcq Single Correct1 Marksmatrix_polynomials
Class 12 Maths · Matrices · Mcq Single Correct #14
If A²=I, simplify (A−I)³+(A+I)³−7A.
✅ Step-by-Step Solution
Final Answer: Option (A): A
- Since A commutes with I, the sum of the two cubes is 2A³+6A. Subtracting 7A gives 2A³−A=A because A³=A.
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