Question

[CALCULUS—OPTIMIZATION] For positive constants A and B, the force between two atoms in a molecule is given by f(r) where r > 0 is the distance between the molecules. What value of r minimizes the force between the atoms?

Answer 1

\[f(r)=-\frac{A}{r^2}+\frac{B}{r^3}\]

Answer 2

Hello stamp

u just need to take the derivative of f(r) and set it equal to zero and solve it for r

Answer 3

That does not work.

Answer 4

why? can u show me ur work ?

Answer 5

\[f'(r)=\frac{2A}{r^3}-\frac{3B}{r^4}\]

Answer 6

quite right and what about solving \[f'(r)=0\]?

Answer 7

2Ar - 3B = 0

Answer 8

and it gives\[r=\frac{3B}{2A}\]

Answer 9

ok :)