Shuai-Yan

困難:

1) y = √(x(√(x√x))) 。求dy/dx

先將化成e的指數形式  記住:a=e^(ln a)

y=(ln x)^x

=e^[x*ln( ln x)]

dy/dx

={e^[x*ln( ln x)]}*d[x*ln( ln x)]/dx　　記住吾好忘記用連鎖律

=[(ln x)^x]*{ln (ln x) + x*d[ln(ln x)]}

=[(ln x)^x]*{ln (ln x) + x*[(1/x)/(ln x)]}

=[(ln x)^x]*[ln (ln x) + 1/(ln x)]

2)點解火車唔夠小明快?

因為小明跑得真係好快