設(shè)參數(shù)方程,確定了y是x的函數(shù),f″(t)存在且不為零,則d2y/d2x的值是:()
A.-1/f″(t) B.1/[f″(t)]2 C.-1/[f″(t)]2 D.1/f″(t)
(x+ex)的值是:()
A.e B.e C.1 D.2
設(shè)參數(shù)方程,確定了y是x的函數(shù),且f′(t)存在,f(0)=2,f′(0)=2,則當t=0時,dy/dx的值等于:()
A.4/3 B.-4/3 C.-2 D.2