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已知g(x)=1-2x,f[g(x)]=,则f()等于( ) A.1 B.3 C.15 D.30
人气:169 ℃ 时间:2020-01-31 02:14:59
解答
若g(x)=1-2x,f[g(x)]=(1-x^2)/x^2,则f(1/2)的值为f[g(x) ]=(1-x^2)/x^2 令g(x)=1/2 1-2x=1/2 2x=1/2 x=1/4 f(1/2)=(1-x^2)/x^2 令x=1/4 有:f(1/2)=(1-(1/4)^2)/(1/4)^2 =15
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