Umm I know that I shouldn’t be using for this but can somebody tell me what im supposed to put for the Applications in my Science fair project cuz im confused and Google doesn’t help me so yeah please tell me im confused

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.