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Function represented by a parametric variable


Function represented by a parametric variable

  1. A function represented by a parametric variable is a mathematical expression composed of numerical values, a parameter (a parametric variable), constants, parentheses, and operators.
  2. A parameter (a parametric variable) is represented by a character 'x'. It is similar to the variable in the usual function.
  3. Constants included in the parametric variable function are specified continuing a positive integer after character 'p'. For instance, it can be expressed by p1 and p2, and so on. It is similar to the parameters in the usual function.
  4. Operators are similar to the usual function.
  5. For instance, for an ellipse, the mathematical expression for coordinate x becomes p1*sin(x) and for y, p1*cos(x), where p1 is a constant, x in each expression for the coordinate x and y is a parameter (a parametric variable), and sin() is an operator. Moreover, in each expression of the coordinate x and y, although the notation of the constant p1 is same, it is treated as a different constant.
  6. If you specify the exponent e(=2.71828) in the parametric variable function, you can use character 'e'.
  7. If you specify (=3.14159...) in the parametric variable function, you can use character string "pi".

Constants

Examples for parametric variable functions

FunctionCoordinateExpression by the parametric variable remarks
Circlexp1*cos(p2*x)Same value must be specified for p1 in x and y, respectively. It is similar for p2.
yp1*sin(p2*x)
Ellipsexp1*sin(p2*x)Same or different value can be specified for p1 in x and y, respectively. For p2, same value must be specified in x and y.
yp1*cos(p2*x)
Cardioidxp1*(1+cos(p2*x))*cos(p2*x)Same or different value can be specified for p1 in x and y, respectively. For p2, same value must be specified in x and y.
yp1*(1+cos(x))*sin(p2*x)
Nephroidxp1*(p2*cos(x)-cos(p2*x))Same value must be specified for p1 in x and y, respectively. It is similar for p2.
yp1*(p2*sin(x)-sin(p2*x))
Nephroidxp1*(p2*cos(x)+cos(p2*x))Same value must be specified for p1 in x and y, respectively. It is similar for p2.
yp1*(p2*sin(x)+sin(p2*x))
Deltoidxp1*(p2*cos(x)+cos(p2*x))Same value must be specified for p1 in x and y, respectively. It is similar for p2.
yp1*(p2*sin(x)-sin(p2*x))


Kazushi Neichi
Department of Business Administration, Tohoku Gakuin University