Solution to Exercise 7.1.1
Alexander Graham Bell. He developed it because we seem to perceive physical quantities like loudness and brightness logarithmically. In other words, percentage, not absolute differences, matter to us. We use decibels today because common values are small integers. If we used Bels, they would be decimal fractions, which aren't as elegant.
Solution to Exercise 7.2.1
Solution to Exercise 7.2.2
Because of Newton's binomial theorem, the sum equals (1 + 1)n =2n .