Sign(); Simult - Texas Instruments TI-NSPIRE Reference Manual

sign()

⇒
Value1 value
sign( )
⇒
List1 list
sign( )
⇒
Matrix1 matrix
sign( )
For real and complex Value1, returns Value1 /
ƒ
Value1
0.
Returns 1 if Value1 is positive.
ë
1 if Value1 is negative.
Returns
„
returns 1 if the complex format mode is Real; otherwise, it
sign(0)
returns itself.
represents the unit circle in the complex domain.
sign(0)
For a list or matrix, returns the signs of all the elements.

simult()

coeffMatrix constVector
simult( ,
Returns a column vector that contains the solutions to a system of
linear equations.
coeffMatrix must be a square matrix that contains the coefficients of
the equations.
constVector must have the same number of rows (same dimension)
as coeffMatrix and contain the constants.
Optionally, any matrix element is treated as zero if its absolute value
is less than tol. This tolerance is used only if the matrix has floating-
point entries and does not contain any symbolic variables that have
not been assigned a value. Otherwise, tol is ignored.
• If you set the
Auto or Approximate
computations are done using floating-point arithmetic.
If tol is omitted or not used, the default tolerance is calculated
•
as:
·
ë
5E 14 max(dim(coeffMatrix))
coeffMatrix constMatrix
simult( ,
Solves multiple systems of linear equations, where each system has
the same equation coefficients but different constants.
Each column in constMatrix must contain the constants for a system
of equations. Each column in the resulting matrix contains the
solution for the corresponding system.
72
Value1
when
abs( )
⇒
tol matrix
[, ])
mode to Approximate,
·
rowNorm(coeffMatrix)
⇒
tol matrix
[, ])
If complex format mode is Real:
Solve for x and y:
x + 2y = 1
ë
3x + 4y = 1
ë
The solution is x= 3 and y=2.
Solve:
ax + by = 1
cx + dy = 2
Solve:
x + 2y = 1
ë
3x + 4y = 1
x + 2y = 2
ë
3x + 4y = 3
ë
For the first system, x= 3 and y=2. For the second system,
ë
x= 7 and y=9/2.
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