Electronic calculator having a graph display function

An electronic calculator having a graph display function, comprising:

• display means including a display region of a certain size for displaying a graph of a given formula having a variable, the display region being adapted to define a range of coordinates for the variable of said formula;
• input means for inputting said formula, and for inputting range data corresponding to a desired range of the value of the variable of the formula for display by the display region;
• formula storage means for storing the formula input by said input means;
• range data storage means for storing the range data input by said input means;
• graph pattern producing means, coupled to said formula storage means and to said range data storage means, for producing graph pattern data of a certain extent, said graph pattern producing means including means for determining the range of coordinates to be defined by the display region of said display means based on the range data input for the variable of said formula;
• display control means, coupled to said display means and to said graph pattern producing means, for supplying the graph pattern data produced by said graph pattern producing means to said display means to obtain the graph display of said formula;
• and
• range changing means, coupled to said range data storage means, for altering the range data stored in said range data storage means for said variable, so that the extent of the graph pattern data produced by said graph pattern producing means is changed based on the range data for said variable as altered by said range changing means, and a new range of coordinates for the variable as determined by the graph pattern producing means is defined for the display region of said display means.