Exercise 4.2.14 let a ⊆ r, let f : a → r, and let c ∈ r be a cluster point of a. if limx→c f exists, and if |f| denotes the function defined for x ∈ a by |f|(x) : = |f(x)|, prove that limx→c |f| = limx→c f .

What is the logarithmic function modeled by the following table? x f(x) 9 2 27 3 81 4

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.