What do you mean "get how it is possible"? You just do exactly what you are told to do. Each term in the Mandelbrot sequence is derived from the previous term by where c and are given. Set up a spreadsheet (using Corel Quattro Pro or Microsoft Excel?) Setting up one column that gives just the integers, 1, 2, 3,..., the next column giving the real component of , the third column giving the imaginary component of , and the fourth column giving the absolute value of .

Exactlyhowyou do that depends upon which spreadsheet program you are using.

For the second problem, What is the area of an equilateral triangle with sides of length 1? The next "stage" in constructing the Koch snowflake is to put small triangle on the middle third of each side. That means you are adding three triangles each of length 1/3. What is the area of an equilateral triangle with side length 1/3? What is the total area of the new triangles? What is the total area of the figure? "Stage 2" requires adding equilateral triangels at the middle third the two "outer" edges of those small triangles as well the two parts of each side of the orginal triangle that are still there. It should be easy to see that the side of each of these new triangles is (1/3)(1/3)= 1/9. What is the area of a right triangle with side length 1/9? It should also be easy to see that you have added 12 such triangles. What is the area of all 12 triangles? What the total area of the new figure?Or this question on the Koch snowflake, where stage 0 is the equilateral triangle:

Calculate the areas for stages 0 to 4 of a snowflake that starts with an equilateral triangle of side 1 unit.

Show that the total area of the Koch snowflake will never exceed 8/5 of the original area.

Can someone show me how to do these? Thanks.

Do that for stage 3 and 4 as well. By that time, you should see that you are adding a specific multiple of the area each time- so getting a geometric series.