4. Suponhamos que Df ⊂ Dg e que f(x) = g(x), ∀x ∈ Df . Então: (A) f(x) = g(x), ∀x ∈ Dg. (B) f é a restrição de g a Df . (C) f é o prolongamento de g a Df . (D) g é a restrição de f a Df

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function.a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.