Aspirin Soon after taking an aspirin, a patient has absorbed 300 mg of the...

Aspirin Soon after taking an aspirin, a patient has absorbed 300 mg of the drug. After two hours, only 75 mg remain, find an exponential model for the amount of aspirin in the bloodstream after t hours, and use your model to find the amount of aspirin in the bloodstream after 5 hours. HINT [See Example 2.]

Example 2:

Find an equation of the exponential curve through (1, 6.3) and (4, 170.1).

Solution We want an equation of the form

Substituting the coordinates of the given points, we get

If we now divide the second equation by the first, we get

Now that we have b, we can substitute its value into the first equation to obtain

We have both constants, A = 2.1 and b = 3, so the model is