Casio fx-CG50 field manual for IB Math
Determinant and inverse of a matrix
Enter a matrix A, compute detA to confirm it is invertible, then compute A−1.
For C=⎣⎡210121012⎦⎤, find det(C) and C−1.
In Run-Matrix, press (▶MAT/VCT) to open the matrix editor. With Mat A highlighted press (DIM) and enter 3 then 3. Type the entries 2, 1, 0, 1, 2, 1, 0, 1, 2, pressing after each value, then twice.
On the Run-Matrix entry line press → (MAT/VCT) → (Det), then insert the matrix with (Mat) and for A. Press .
The determinant is nonzero, so the inverse exists. Insert Mat A again with → (MAT/VCT) → (Mat) , then press for x⁻¹ and . With Input/Output set to Math the Casio shows the inverse with fractional entries.
det(C)=4 and C−1=41⎣⎡3−21−24−21−23⎦⎤=⎣⎡43−2141−211−2141−2143⎦⎤.
Your turn
Work each one on your calculator, then check the answer.
- 1
For A=⎣⎡211121112⎦⎤, find det(A) and A−1.
- 2
For B=⎣⎡310121012⎦⎤, find det(B) and B−1.
- 3
For C=⎣⎡102210031⎦⎤, find det(C) and C−1.