设f(x)连续且f(x)≠0,又设f(x)满足f(x)=∫0xf(z—t)dt+∫01f2(t)dt,则f(x)=___________.

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问题 设f(x)连续且f(x)≠0,又设f(x)满足f(x)=∫0xf(z—t)dt+∫01f2(t)dt,则f(x)=___________.

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答案[*]

解析 f(x)=∫0xf(x—t)dt+∫01f2(t)dt(第—个积分令x—t=u)
    =一∫x0f(u)du+∫01f2(t)dt=∫0xf(u)du+∫01f2(t)dt.
令∫01f2(t)dt=a,于是
    f(x)=∫0xf(u)du+a,f’(x)=f(x),f(0)=a,
解得f(x)=Cex.由f(0)=a,得f(x)=aex,代入∫01f2(t)dt=a中,得
    a=∫01f2(t)dt=a201e2tdt=(e2—1).
解得a=0(舍去),a
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