Help in R

I don?t know if my question is answerable, but it is worth a try. I have a data set that I am trying to analyze in R for a course and the instructions were to get a standard deviation which I already computed in R and use that number and change it to a biased standard deviation?.(I have the two equations and I understand the difference between the two and how the unbiased has the degree of freedom?..I just do not know how use my standard deviation and transform it in R to a biased one.
Thanks in advance,
Jessie