Condition Judgment (judge, piecewise)u“judge” Function

The “judge” function returns TRUE when an expression is true, and FALSE when it is false.

Problem

 

Operation

Is the following expression true or false?

[judge] 1 = 1 w

1 = 1

TRUE

 

 

 

Is the following expression true or false?

[judge] 1 < 0 w

1 < 0

FALSE

 

 

 

 

u“piecewise” Function

The “piecewise” function returns one value when an expression is true, and another value when the expression is false.

The syntax of the “piecewise” function is shown below.

piecewise(<condition expression>, <return value when true>, <return value when false or indeterminate> [ ) ] or

piecewise(<condition expression>, <return value when true>, <return value when false>, <return value when indeterminate> [ ) ]

Use the soft keyboard (1) to input “piecewise” function according to the syntax shown below.

<return value when true>, <condition expression>

<return value when false or indeterminate>

or

<return value when condition 1 is true>, <condition 1 expression> <return value when condition 2 is true>, <condition 2 expression>

Problem

Operation

 

For the expression 0 t x (x = variable), return 1

[piecewise] 0 :X, 1 , 2 w

when x is 0 or less, and 2 when x is greater than 0

or

 

or undefined.

11 c 2 ef 0

:X w

 

 

 

For the expression 1 t x (x = variable), return 1

11 c 2 ef 1

:X c 1 <Xw

when x is 1 or less, and 2 when x is greater than 1.

 

 

 

Angle Symbol (∠)

Use this symbol to specify the coordinate format required by an angle in a vector.

You can use this symbol for a vector only.

Problem

 

Operation

Convert the polar coordinates r = '2 , θ = π /4 to

Change the [Angle] setting to “Radian”.

rectangular coordinates.

[1, 1]

[toRect] [5 2 e,~7/ 4 )]w

 

 

 

Derivative Symbol (’)

A single derivative symbol indicates the first derivative of an equation in the format: <variable name>’.

Problem

Operation

Solve the differential equation y’ = x.

{y = 0.5 · x2 + const (1)}

Important!

+Y'=X,X,Yw

The “dSolve” function can solve differential equations up to three degrees, so a maximum of three derivative symbols (y’’’) can be used. Executing a “dSolve” calculation that has more than three derivative symbols will result in an Invalid Syntax error.

Chapter 2: Main Application

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