Answer:
Step-by-step explanation:
Let r be the radius of circular top and h be the height of the cylinder 
Given
π r² h = 1000
Let cost of making side of can be p per unit area , the cost of making top and bottom will be 2p per unit area. 
total cost 
C = 2 x π r² x 2p + 2πrh x p 
= 2(1000 / h) x 2p + 2π x (1000 / π) x 
 x h x p
 x h x p 
= 2(1000 / h) x 2p + 2π x (1000 / π) x √h x p 
differenciating 
dC / dh = 2(- 1000 / h²) x 2p + 2π x (1000 / π) x 
 x p = 0 for minimum cost
 x p = 0 for minimum cost 
- 4 / h² + 1 / √h = 0
h³ = 16 
h = 2.519 cm . 
π r² h = 1000
π r² x 2.519 = 1000
r = 11.24 cm 
The cylinder will have height of 2.519 cm and radius of 11.24 cm.