*Constants* Use pi for the usual 3.14159.... Use e for the base of the
natural log, 2.71828....

*Functions* The argument to a function must be surrounded by
parentheses, like abs(x). The function grapher understands the following
functions.

abs | Absolute value. You may also use |x|. |

sqrt | Square root. |

cbrt | Cube root. |

root | General root: root(5,x) computes the fifth root of x. |

! | Factorial. Use x! for x factorial. |

exp | Exponential with base e. exp(x) is the same as e^x. |

log, ln | Logarithm with base e. |

sin | Sine function. |

cos | Cosine function. |

tan | Tangent function. |

sec | Secant function. |

csc | Cosecant function. |

cot | Cotangent function. |

arcsin | Inverse sine function. |

arccos | Inverse cosine function. |

arctan | Inverse tangent function. |

sinh | Hyperbolic sine function. |

cosh | Hyperbolic cosine function. |

tanh | Hyperbolic tangent function. |

*Summation* You can define a function using summation notation. For
example, sum(x^n,n,1,4) is the same as x+x^2+x^3+x^4. In general, use sum(expr,var,start,end)
to sum the expression expr for values of var (which is allowed to be any single
letter other than x or e) from start to end in increments of 1. Use sum(expr,var,start,end,incr)
to use an increment other than 1.

*Sequences of Functions* You can graph a sequence of functions
depending on a parameter. For example, seq(x^n,n,1,4) is the same as
x;x^2;x^3;x^4. In general, use seq(expr,var,start,end) to graph the expression
for values of var (which is allowed to be any single letter other than x or e)
from start to end in increments of 1. Use seq(expr,var,start,end,incr) to use an
increment other than 1. You may graph a sequence of sequences, but sequences may
not otherwise appear inside functions.

*Logical Expressions* You may use logical expressions that evaluate to
0 when false and 1 when true. These are useful for graphing piecewise-defined
functions, for example. You may use the comparison operators =, <, >,
<= (less-than-or-equal), >= (greater-than-or-equal), and != (not-equal).
You may use the logical operators & (and), | (or), and ! (not). So, for
example, (x<3)&!(x<2) evaluates to 1 when x is less than 3 and not
less than 2, but evaluates to 0 otherwise. The parentheses are actually optional
in that expression.

*Tick Marks* You may specify the spacing of tick marks. The grapher
tries to be smart about drawing its tick marks, however. The actual spacing of
the tick marks will be a power of 10 times the spacing you specify, chosen so
that the tick marks are spaced not too close together or too far apart.

*Selecting a Region* You may select a region of the graph for use in
zooming (below) by clicking and dragging with the mouse (left-most button for
multiple button mice).

*Zooming In* Choosing Zoom In from the menu, or clicking on the Zoom
In button, does one of two things. If you have selected a region of the graph as
above, that region is enlarged to fill the whole graph. Otherwise, zoom in
towards the center of the graph by a factor of 2.

*Zooming Out* Choosing Zoom Out from the menu, or clicking on the Zoom
Out button, does one of two things. If you have selected a region of the graph,
the visible graph is shrunk to fit inside that selection. Otherwise, zoom out
away from the center of the graph by a factor of 2.

*Squaring Up* Choosing Square Up from the menu or clicking on the
Square Up button will adjust the graph so that 1 unit on the x-axis looks the
same length as one unit on the y-axis.

*Tracing* If you choose Trace from the menu the grapher will trace
your mouse movements along one of the graphs. An X will be drawn on the point of
the graph with the same x-coordinate as the mouse, and the coordinates of that
point will be shown below the graph, together with the expression that defines
that function. If you are graphing more than one function, you can change which
function is being traced by choosing Next Function or Previous Function from the
menu, clicking on the buttons of the same names, or using the down and up arrows
on your keyboard (you may have to click somewhere in the graph to get the arrow
keys to work).

*Ultimo aggiornamento: giugno 2005
realizzato da Gianfranco Bo*