Quick Memory Keys — Say These Out Loud!
DAISY
2×2 Determinant
Diagonal Ad Inverse Subtract Yield
→ \(ad - bc\)
→ \(ad - bc\)
LMR
3×3 Trick
Left diags minus Middle = Right diags
→ aei+bfg+cdh − bdi−afh−ceg
→ aei+bfg+cdh − bdi−afh−ceg
ZERO
No Inverse
det = 0 → No inverse!
Singular matrix = stuck
Singular matrix = stuck
FLIP
2×2 Inverse
Flip diagonal, Lnegate off-diag, I÷det
\(\frac{1}{ad-bc}\begin{bmatrix}d&-b\\-c&a\end{bmatrix}\)
\(\frac{1}{ad-bc}\begin{bmatrix}d&-b\\-c&a\end{bmatrix}\)
🏆
Quiz Complete!
0/20
Keep practicing!