JAMB - Mathematics (2001 - No. 28)
Find the rate of change of the volume, V of a sphere with respect to its radius, r when r = 1.
12π
4π
24π
8π
คำอธิบาย
Volume of sphere, V = 4/3 x πr3
Rate of change of V = dv/dr
Thus if V = 4/3 x πr3,
=> dv/dr = 4πr2
At r = 1, Rate = 4 x π x 1 = 4π
Rate of change of V = dv/dr
Thus if V = 4/3 x πr3,
=> dv/dr = 4πr2
At r = 1, Rate = 4 x π x 1 = 4π