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Please print out a copy of Experimental and analytic predictions (.ps or .pdf) for guidance on presenting data in computer science classes.
As you know, plain graph paper is universally helpful for presenting data. Semi-log paper is useful for presenting rapidly growing functions. In particular, if you print an exponential function on semi-log paper, you'll end up with a straight line. The slope of the line determines the base of the exponent. If you turn semi-log paper on it's side, you can use it to plot logarithmic functions; again, you should get a straight line.
On log-log paper, polynomials end up looking like straight lines. The slope of the line determines the degree of the polynomial.
If you've never seen log-paper before, the bottom row (marked ``1'') is 1 unit. The next line marked ``1'' is 10 units. The next ``1'' after that is 100 units, then 1000. The very top line would be 100,000 on the 5-cycle semi-log paper.