設(shè)f(x)的一個(gè)原函數(shù)為cosx,g(x)的一個(gè)原函數(shù)為x2,則f[g(x)]等于:()
A.cosx2 B.-sinx2 C.cos2x D.-sin2x
設(shè)4/(1-x2)·f(x)=d/dx[f(x)]2,且f(0)=0,則f(x)等于:()
A.(1+x)/(1-x)+c B.(1-x)/(1+x)+c C.1n|(1+x)/(1-x)|+c D.1n|(1-x)/(1+x)|+c
不定積分[f′(x)/(1+[f(x)]2)]dx等于()
A.ln|1+f(x)|f+c B.(1/2)1n|1+f2(x)|+c C.arctanf(x)+c D.(1/2)arctanf(x)+c