According to an educational psychologist, the number of words learned by a student of a foreign language after t hours in the language laboratory is given by f (t) = 42,000 (1 – e-0.00012) How many hours would it take for a student to learn 18, 000 words?

Vivian takes a 425 mg aspirin for her headache. The amount of aspirin remaining in her system decays exponentially according to the model A=425⋅(0.855)tA=425⋅(0.855)t, Where AA is in milligrams (mg) and tt is in hours after she takes the aspirin. Answer the following questions, rounding each to the nearest whole mg. (a) How much aspirin is in Vivian's system immediately after taking the aspirin?    (b) How much aspirin is in her system after 3 hours?    (c) How much aspirin is in her system if she takes another aspirin 4 hours after the first?

2. Evaluate the following expressions without the calculator: a. log: 81 In (1) b. c. log 0.24 d. log6 67 e. log 8 2