The MS Excel "use function" proposition:

1. There are some article prices in the attached file (version for the Openoffice) (Czech only...). The table values are regularly generated at random. All the calculation should accept changes in the parameters, signed by the yellow background (use absolute address to them, or set names for them).
   Subtasks:
   1. insert some reasonable equations into the cells marked by the cyan background.
   2. use reasonable format, currency etc. (including the € sign, or "Kč", where required).
   3. the discount should be calculated in the cell F48, depending E45 to F45.
   4. The F49 should be F48 multiplied by the VAT (volume added tax)..
   5. set up the appropriate grid for the cyan cells.
   6. create a pie-chart graph of the resulting values, sign each of pie slice by the name of the category.
      
2. Draw the function according the proposition's page (link)  in the range of -90° to 450° with main gridlines  of 90° and minor gridlines of 30°.
   
3. Using matrix multiplication and inversion, solve the system of linear equations from the proposition's page:

   Individual proposition for the tasks 2 and 3

   Test the result.