Question

What kind of function best models each situation? write linear, quadratic, exponential, trigonometric, or piecewise.

1. a radioactive element has a half-life of 20 minutes. a sample contains 66 g of the element. a function models the amount of the sample remaining as a function of time.

2. a function models the nth term in the following sequence: 8.5, 5, 1.5, -2, -5.5, ...

please help and thank you. much appreciated. ​

Answer 1

1. exponential
2. linear

Explanation:

1. Any time you see "half-life", "doubling time", "compound interest", "change proportional to quantity", or similar, the model is exponential.

___

2. The differences from one term to the next are -3.5. When differences are constant, the function is linear.