In this page, to deal with the Mathematics function of school textbook.
    Mainly, Differential, Integral and Calculation of sum I£.
    c.f. Sample Program: "smp_diff.bas"
    Practical usage is described at lower part of the reference.
    
    The formula about 'x' are dealt with by character string.
    So formula level operations in string are possible.
    
    About omission of "*"
    3x^2+4x+1a??a?|(1)
    3*x^2+4*x+1a??a?|(2)
    
    In mathematics, it is usually written like -(1).
    The formula recognized by 'Basic' need '*'(multiplication)
     in front of the variable'x' without omission like -(2).
    
    The formula to give to function, it is possible to use both (1) and (2).
    ((1) is converted to (2) internally, and processed)
    The formula(string) returned by function is always returned in format-(2).
    
    The formula(string) returned by format-(2),
    it is, -by assigning a numerical value for 'x',
    it can calculate by 'calc()' as it is, and able to get the value.
    
    e.g.
    f$=fcal("x+3","2*x+2","add") :'2-formulas are added and result'3*x+5' enter to 'f$'
    x=2 :'substitute 2 for x
    print calc(f$) :'calculate '3*x+5' with assigned value
     11 :'result'11' is displayed
    
    And, 'x'-coefficient of formula's calculation result,
     it may become irrational number which cannot divide,
     then, the result output of formula will be returned by not [a decimal]
     but [fraction enclosed by parentheses], like a "(1/3)*x^3+(5/2)*x^2".
    
    e.g. in the case of integral calculation
     print intgr$("x^2+5*x")
     (1/3)*x^3+(5/2)*x^2
    
 

  GCD


  [Features]  To find solution of greatest common divisor.

  [Format]  GCD(n1,n2)

  [e.g.]
     print gcd(30,42)
      6
     

 

  LCM


  [Features]  To find solution of least common multiple.

  [Format]  LCM(n1,n2)

  [e.g.]
     print lcm(30,42)
      210


 

  PRIME


  [Features]  To return the first prime number on and after a specified number.

  [Format]  PRIME(n)

  [Explanation]
     When n is a prime number, n is returned,
     so it can also use for distinction of whether n is prime number.
     
  [e.g.]
     print prime(12)
      13


  ROOT


  [Features]  To find the n-th root of x.

  [Format]  ROOT(n,x)

  [Explanation]
     This is an approximation.
     n√x (n is dimensions number, the upper left mini symbol, not multiplication)
     A number that is multiplied by 'n' times to became 'x'.
     SQR is only the square, it can find n-th root of three or more dimensions.

  [e.g.]
     r=root(3,100)
     print r
      4.6415889136718755
     print r^3
      100.00000517446294


 

  FAC


  [Features]  The factorial of n is returned.

  [Format]  FAC(n)

  [Explanation]
     (The product of all the integers from 1 to n)
     The case of 'fac(5)', it will be 1*2*3*+4*5=120.

  [e.g.]
     print fac(5)
      120


 

  PERM


  [Features]  To return number of cases of permutation of mathematics.

  [Format]  PERM(n,r)

  [Explanation]
     It is calculation represented by 'nPr'.
     The total number of branches that take 'r' pieces out
      from different 'n' pieces, and put in order.
     The case of '6P3', it will be 6*5*4=120.

  [e.g.]
     print perm(6,3)
      120


 

  COMB


  [Features]  To return number of cases of combination of mathematics.

  [Format]  COMB(n,r)

  [Explanation]
     It is calculation represented by 'nCr'.
     The total pattern number that select 'r' pieces from different 'n' pieces.
     This value is obtained by PERM(n,r)/FAC(r).

  [e.g.]
     print comb(5,3)
      10


 

  SIGMA


  [Features]  The sum of number sequence is calculated.(mathematics Σ)

  [Format]  SIGMA(n1,n2)

  [Explanation]
      4
      Σ  (x+1)    (in this case n1=1,n2=4)
     x=1
     The case 'sigma("x+1",1,4)' then,
      to substitute '1 to 4: increasing' for 'formula x',
      and the value adding all the results is returned.
     This 'formula of Σ' can be calculated including general functions as sin(),cos(),etc.

     It also have the function to make various settings.
     Form2: sigma("int"|"even"|"odd")
     Although increment is usually 1,(default a=sigma("int"))
     it can specify the following.
     add only when even: a=sigma("even")
     add only when odd : a=sigma("odd")

     And although the target variable is 'x' by default,
      it can change into any variables by 'a=sigma("v:y")'.
     Form2: sigma("v:1chaVariableName")
     (to describe 1character Variable-Name next to "v:)
     The variable specified here is also applied to target variable of
      differential/Integration/fcal function.

  [e.g.]
     print sigma("2*x^2+1",1,4)
      64
     a=sigma("v:y")
     print sigma("2*y^2+1",1,4)
      64
     a=sigma("odd"):a=sigma("v:x")
     print sigma("2*x^2+1",1,4)
      22


  DERIV$


  [Features]  The given formula is differentiated and it is made a Derivative function.

  [Format]  DERIV$(formula-string)

  [Explanation]
     The result is returned by the formula of a character string.
     f'(x)=lim  f(x+h)-f(x)
             h→0      /h
     formula "x^n" then, Derivative function of result will be "n*x^(n-1)"

  [e.g.]
     print deriv$("x^2+2*x+1")
     2*x+2


 

  DIFF


  [Features]  To find solution of Differential coefficient.

  [Format]  DIFF(formula-string,n)

  [Explanation]
     The formula is made into Derivative function,
      and the value which substituted 'n' for 'x' is acquired.
     Differential coefficient will be the slope of a tangent at the time of the formula'x=n'.

  [e.g.]
     print diff("x^2+2*x+1",4)
      10


  INTGR$


  [Features]  The given formula is integrated and it is made a Primitive function.

  [Format]  INTGR$(formula-string)

  [Explanation]
     ∫   f(x) dx    [f(x) is "2*x+2" in example case]
     It is returned by the formula of a character string.
     Integration is the inverse operation of differentiation.
     formula "a*x^n" then, the result formula of integration will be "a/(n+1)*x^(n+1)"
     The result is the one without the integral constant 'C'.

  [e.g.]
     print intgr$("2*x+2")
     x^2+2*x
     print intgr$("x^2+5*x")
     (1/3)*x^3+(5/2)*x^2


  DINT


  [Features]  To find solution of Definite integral.

  [Format]  DINT(formula-string,n1,n2)

  [Explanation]
     4
     ∫   f(x) dx     [f(x) is "2*x+2" in example case]
     1
     The formula is made into Primitive function F(x),
      and substitute 'x' for 'n1' and 'n2',
      and the value F(n2)-F(n1) is acquired.
     When formula is 'x^2', Definite integral result become an area of part
      enclosed between x-axis and parabola of formula, range n1<=x<=n2.

  [e.g.]
     print dint("2*x+2",1,4)
      21


  FCAL


  [Features]  To calculate formula 1 and 2 for 'x'(default) given by string, and return the result as string.

  [Format]  FCAL(formula-string1,formula-string2,"add"|"sub"|"mult")

  [Explanation]
     To specify "add" or "sub"(subtraction) or "mult"(multiplication) with 3rd parameter.
     It is possible to calculate formula whose coefficient is integer.
     The formula including fractions are not supported at the moment.

  [e.g.]
     print fcal("x+3","2*x+2","add")
     3*x+5
     print fcal("x^2+1","2x-2","mult")
     2*x^3-2*x^2+2*x-2




Next are the chemistry functions.


  CHEM$


  [Features]  This retrieves various physical properties and basic information regarding chemical elements.

    ## [1] Basic Usage
    The basic syntax of the function is as follows. Both parameters are passed asstring values.
```
    CHEM$("Element Number or Name", "Property Name")
    
    ```
    
    ■ Parameter Specifications
    
    [1st Parameter: Element Identifier]
    ・Atomic Number : "1" to "118" (zero-padding such as "01" is supported)
    ・Symbol : "H", "Fe", etc.
    ・English Name : "Hydrogen", "Iron", etc.
    
    [2nd Parameter: Property Identifier]
    ・Property Index: "1" to "30"
    ・Property Name : "Melting Point", "Atomic Weight", etc.
    
    ■ Notation Flexibility
    ・English inputs are case-insensitive ("FE", "fe", and "Iron" are all accepted).
    ・Slash-separated property names (e.g., "Classification/Element Classification")
    can be abbreviated to "Classification" or "Element Classification".
    
    ---
    
    ## [2] Unit Display Toggle (Special Command)
    
    You can toggle whether physical units (℃, g/cm³, kJ/mol, pm, etc.) are attached
    to the returned values.
    
    ・Enable Units (ON) : chem("unit", "on")
    ・Disable Units (OFF): chem("unit", "off") *Default setting
    
    ---
    
    ## [3] Return Value Specifications & Data Formats
    
    All return values are provided as String types. Output data falls into three
    structural formats. When parsing returned values in your application, split
    the strings accordingly.
    
    (1) Single Data
    Example: "1537", "Solid"
    
    (2) Multiple Data (Comma ',' separated)
    Example: "737.7,1450.7", "+2,+3"
    
    (3) Range Data (Tilde '~' separated)
    Example: "12~34" (Used for atomic weights or densities with natural variation)
    
    *Notes
    ・When the unit flag is set to ON, units are appended to each individual value
    in multiple or range data.
    (e.g., "737.7 kJ/mol,1450.7 kJ/mol" / "12 g/cm³~34 g/cm³")
    ・For unmeasured properties, non-existent elements, or invalid property queries,
    an empty string "" is returned.
    
    ---
    
    ## [4] Supported Property Index (All 30 Properties)
    
    No | Property Name
    ----+---------------------------------------------------------------------------
    1 | Atomic Number
    2 | Symbol
    3 | Element Name/English Name
    4 | (Reserved for local language name)
    5 | Mass Number
    6 | Atomic Weight/Relative Atomic Mass
    7 | Electron Configuration
    8 | Crystal Structure
    9 | CAS Registry Number
    10 | Discovery Year
    11 | Discoverer/Country of Discovery
    12 | Classification/Element Classification
    13 | State/State of Matter
    14 | Radioactivity
    15 | Isotopes
    16 | Representative Compounds
    17 | Group Number
    18 | Period Number
    19 | Melting Point
    20 | Boiling Point
    21 | Specific Gravity
    22 | Density
    23 | Oxidation State/Valence
    24 | Electronegativity
    25 | Electron Affinity
    26 | Ionization Energy
    27 | Atomic Radius
    28 | Covalent Radius
    29 | Van der Waals Radius
    30 | Hardness/Mohs Hardness/Vickers Hardness
    
    ---
    
    ## [5] Property Descriptions & Data Variations
    
    Fundamental properties (Atomic Number, Period, Group, CAS Number, etc.) are
    fixed, standardized values. Conversely, physical quantities and microscopic
    properties (radii, hardness, oxidation states, etc.) may vary across databases
    depending on experimental conditions, sample purity, allotropes, and theoretical
    models. These values should be used as approximate guidelines.
    
    1. Atomic Number
    The number of protons in the atomic nucleus.
    2. Symbol
    1 to 2-letter chemical symbol.
    3. Element Name/English Name
    Standard English name registered with IUPAC.
    5. Mass Number
    Total number of protons and neutrons in the most common isotope.
    6. Atomic Weight/Relative Atomic Mass
    Average mass of natural isotopes.
    *An increasing number of elements are listed as ranges in standard IUPAC
    tables due to isotopic abundance variations depending on geological origin.
    7. Electron Configuration
    Distribution of electrons across electron shells (K shell outward).
    8. Crystal Structure
    Representative crystal lattice of the element at room temperature and pressure.
    *May vary with allotropes or temperature.
    9. CAS Registry Number
    Unique international identifier for chemical substances.
    10. Discovery Year
    The year the element was isolated, identified, or synthesized.
    11. Discoverer/Country of Discovery
    Name of the discoverer and the country where research was conducted.
    12. Classification/Element Classification
    Categorization by chemical behavior (Metal, Nonmetal, Noble Gas, Alkali Metal,
    etc.).
    13. State/State of Matter
    Physical state (Solid, Liquid, Gas) under standard conditions (25°C, 1 atm).
    14. Radioactivity
    Indicates whether the element lacks stable isotopes and is radioactive.
    15. Isotopes
    Major naturally occurring isotopes and their relative abundances
    (Mass Number|Abundance %).
    16. Representative Compounds
    Common chemical formulas formed by the element.
    17. Group Number
    Vertical columns in the periodic table (Groups 1–18).
    18. Period Number
    Horizontal rows in the periodic table (Periods 1–7).
    19. Melting Point / 20. Boiling Point
    Phase transition temperatures.
    *Sublimation at high temperatures or theoretical calculations for superheavy
    elements can lead to variations across sources.
    21. Specific Gravity / 22. Density
    Mass per unit volume.
    *Values may span a range due to allotropes, crystal defects, or differing gas
    measurement standards.
    23. Oxidation State/Valence
    Common oxidation states in compounds.
    *Sources differ on whether they list only primary oxidation states or include
    rare states.
    24. Electronegativity
    Tendency of an atom to attract shared electrons.
    *Values depend on the scale used (e.g., Pauling scale, Allred-Rochow scale).
    25. Electron Affinity
    Energy released when an electron is added to form a negative ion
    (1st electron affinity).
    26. Ionization Energy
    Energy required to remove an electron to form a positive ion.
    27. Atomic Radius / 28. Covalent Radius / 29. Van der Waals Radius
    Measures of atomic size.
    *Values vary significantly across research groups depending on experimental
    method (e.g., X-ray crystallography), coordination number, and bonding models.
    30. Hardness/Mohs Hardness/Vickers Hardness
    Resistance to scratching or indentation.
    *Values fluctuate between databases due to crystal orientation, purity, and
    measurement difficulties in ductile metals.