NCERT Class 12 · Ch 4 Exercise 4.1 · Q1
NCERT Class 12 Maths · Chapter 4 Determinants · Exercise 4.1 Question 1
Evaluate the determinant of \(\left[\begin{matrix}2 & 4\\-5 & -1\end{matrix}\right]\).
💡 Concept Hints
- Identify whether this needs determinant expansion, an inverse, or the absolute determinant formula for area.
- For a determinant use signed cofactors. For a system first check invertibility; for an area take half the absolute determinant.
✅ Step-by-Step Solution
Final Answer: \(18\)
- For a 2×2 matrix use det A=a₁₁a₂₂−a₁₂a₂₁.
- \(-2\) − \(-20\) = \(18\).
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