Your program does not calculate the average correctly. How might you have known that an error existed?

Select 4 options.

1. user feedback

2. print debugging

3. A user complained about the language used in the program.

4. test cases

5. automated testing

For positive constants a and b, the force between two atoms in a molecule is given f(r) = −a r2 + b r3 , where r > 0 is the distance between the atoms. note: a and b are upper case letters. (a) find f '(r) = (b) find the critical point for f(r). r = (c) find f ''(r) = (d) find the value of r so that f ''(r) = 0.