How do i solve for the derivative of y=r/sqrt(r^2+1)?

The line containing the midpoints of the legs of right triangle abc where a(-5,5), b(1, 1), and c(3, 4) are the vertices.

8.74 rounded to the nearest whole number

Novak gives 9 packs of paper to a group of 5 students. if the group shares the paper equally how many packs of paper does each student get. write the a answer as a mixed number