Mathematic formulas

This is a sample formula:
1#1
2#2

And this is an inline formula: 3#3 and so it goes.


4#4 5#5 6#6(1)
  5#5 7#7(2)

Testing single variables: 8#8, 9#9, 10#10.

Test of Figure environment:

11#11

Test using eqnarray:

12#12 5#5 13#13(3)
14#14 5#5 15#15(4)

Test using eqnarray*:

16#16
First as an equation:
  17#17 (5)
Then using displaymath:
17#17
followed by more text.