The given functions all have limits of 0 as x → 0+. For each function, find how close the input must be to 0 for the output to be a) within 0.1 of 0, and b) within 0.01 of the limit. Sketch a graph of each function for x < 1, and say which functions approach 0 quickly and which approach 0 slowly.
f4(x) = x4.