Hi,
Im doing a differentiation problem and somewhere i am going wrong so I am just going to type out my work and see if anyone can help
Surface are of cylinder is 60cm and we need to find the maximum and minimum volume
2pi r(h+r)=60
h+r= 60/2pi r
h+r=30/ pi r
h= (30/pi r) -r
h= (30-pi r^2)/ pi r)
placing h into volume formula
v= pi r^2*h
substituting h leaves -pi r^3+30r
dr/dv= -3r^2+30r=0
3r(-r+10)
r=10
where do i go from here.
how do i find the maximum and minimum??