Parametric graphs

Create this kind of graph to plot any explicit function in the form:

Click the button Formula  or select menu item <Data><Formula> to create this kind of graphs. This will cause the Formula dialog box show, where you can modify properties of graph (formula, range of parameters u and v, color, width and so on). It is possible to draw families of lines with a given step of parameter v.

Notes:

The set of operations and functions.

When prompted to enter a formula the set of operations and functions you may use is the following.

Arithmetic operators:

+
a + b
-
a - b
*
a * b
/
a / b
^
a ^ b (a to the power of b)

Built-in functions:

sin(u)
Sine, the angle 'u' must be in units of radians.
sind(u)
Sine, the angle 'u' must be in units of degrees.
cos(u)
Cosine
cosd(u)
tan(u)
Tangent
tand(u)

asin(u)
Inverse sine
acos(u)
Inverse cosine
atan(u)
Inverse tangent

rad(u)
Converts an angle measured in degrees to the equivalent number of radians.

exp(u)
Exponent (i.e e to the power of u)
ln(u)
Natural logarithm (base e)
log(u)
Logarithm base 10
pow(u, v)
u to the power of v
sqr(u)
Square root
factorial(u)
u!, if u value is not an integer, it is truncated.

sinh(u)
Hyperbolic sine
cosh(u)
Hyperbolic cosine
tanh(u)
Hyperbolic tangent

besselj0(u)
Bessel functions of the first kind: orders 0, 1, and n, respectively
besselj1(u)
besseljn(u, v)
bessely0(u)
Bessel functions of the second kind: orders 0, 1, and n, respectively
bessely1(u)
besselyn(u, v)

gamma(u)
Integral( x^(u-1)*exp(-x) ), with x limits from 0 to infinite
beta(u, v)
Integral( x**(u-1)*(1-x)**(v-1) ) with x limits from 0 to 1
normal(u, v)
exp( -u*u/4/v/v )/v/sqrt(2*pi)
normln(u, v)
exp( -ln(u)*ln(u)/4/v/v )/v/sqrt(2*pi)
&nbsd;

expdist(u, v)
v*exp(-v*u)
expdistc(u, v)
1 - exp(-v*u)
The formula is the integral from 0 to u value of expdist(u, v).
&nbsd;
poison(u, v)
exp(-v)*v^u/u!, if u value is not an integer, it is truncated.
&nbsd;
fisher(u)
0.5*ln((1+u)/(1-u)), the Fisher transformation at u
fisheri(u)
(exp(2u) - 1)/(exp(2u) + 1), the inverse Fisher transformation

abs(u)
Absolute value
int(u)
Integer part of u
max(u,v)
Maximum of u and v
min(u,v)
Minimum of u and v

sign(u)
Sign of u. If u is less than 0, the value of the function is -1. If u is equal to 0, the value of the function is 0. If u is greater than 0, the value of the function is 1.
step(u,v)
Step function. If u is less than v, the value of the function is 0. If u is greater than or equal to v, the value of the function is 1. If you need a function which is 1 up to a certain value and then 0 beyond that value, use the expression step(v,u).

random(u)
Random number generator, generates a random floating point number such that 0 ≤ Result < u

effect(u, v)
(1 + u/v)^v - 1, financial function.
u is the nominal interest rate,
v is the number of compounding periods per year.

Predefined constants::

pi
3.141592654
e
2.718281828

See example.