HP 15c User Manual

Page 150

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150 Section 12: Calculating with Matrices

One-Matrix Operations:

Sign Change, Inverse, Transpose, Norms, Determinant

Keystroke(s)

Result in

X-register

Effect on Matrix

Specified in

X-register

Effect on Result

Matrix

“

No change.

Changes sign of
all elements.

None. ‡

∕
(´∕ in
User Mode)

Descriptor of
result matrix.

None. ‡

Inverse of
specified matrix.
§

´>

4

Descriptor of
transpose.

Replaced by
transpose.

None. ‡

´>

7

Row norm of
specified
matrix.*

None.

None.

´>

8

Frobenius or
Euclidean norm
of specified
matrix.

†

None.

None.

´>

9

Determinant of
specified
matrix.

None.‡

LU decomposi-

tion of specified
matrix.§

*

The row norm is the largest sum of the absolute values of the elements in
each row of the specified matrix.

†

The Frobenius of Euclidean norm is the square root of the sum of the
squares of all elements in the specified matrix.

‡

Unless the result matrix is the same matrix specified in the X-register.

§

If the specified matrix is a singular matrix (that is, one that doesn’t have an
inverse), then the HP-15C modifies the LU form by an amount that is
usually small compared to round-off error. For ∕, the calculated inverse
is the inverse of a matrix close to the original, singular matrix. (Refer to the
HP-15C Advanced Functions Handbook for further information.)

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