Class 12 Matrices · Conceptual Answer1 Marksmatrix_equality
Class 12 Maths · Matrices · Conceptual Answer #36
For A=\(\begin{bmatrix}\cos\alpha & -\sin\alpha\\\sin\alpha & \cos\alpha\end{bmatrix}\), find all real α for which A=I₂.
✅ Step-by-Step Solution
Final Answer: α=2kπ, k∈Z.
- Corresponding entries require cosα=1 and sinα=0, whose simultaneous real solutions are α=2kπ.
- α=2kπ, k∈Z.
📋 CBSE Stepwise Marking Scheme
- [0.5 marks] Corresponding entries require cosα=1 and sinα=0, whose simultaneous real solutions are α=2kπ.
- [0.5 marks] α=2kπ, k∈Z.
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