V = 4/3πR3(t) = ct
兩邊求導(dǎo):
4πR2(t)R’(t) = c
R(t)R’(t) = c/(4πR(t))
球表面積:
A(t) = 4πR2(t)
兩邊求導(dǎo):
A’(t) = 8πR(t)R’(t) = 8π*c/(4πR(t))
= 2c/(R(t))
球的表面積的增長(zhǎng)速度與球半徑成反比,比例系數(shù)為2c.