How to find growth rate of function?

Question

I have three functions, and I have to order them according to their relative growth rates (in increasing order). Following are the functions given:

f(x)=

f(x)=

f(x)=

I am not understanding that how do I find growth rate?

Answer 1

To find the growth rate, you could use a spreadsheet and draw graphs for different values.

Once you've done that, take a graph and look at the shape and place them in order of how they grow. Here's a clue 20 * n^18 is much much bigger than log20(n^18).