已知函數(shù)f(x)滿足f(x+1)=-f(x),且f(x)是偶函數(shù),當(dāng)x∈[0,1]時(shí),f(x)=x
2,若在區(qū)間[-1,3]內(nèi),函數(shù)g(x)=f(x)-kx-k有4個(gè)零點(diǎn),則實(shí)數(shù)k的取值范圍是( )
A.
[,)B.
(0,)C.
(0,]D.
(,)
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∵函數(shù)f(x)滿足f(x+1)=-f(x),故有f(x+2)=f(x),故f(x)是周期為2的周期函數(shù).再由f(x)是偶函數(shù),當(dāng)x∈[0,1]時(shí),f(x)=x
2,
可得當(dāng)x∈[-1,0]時(shí),f(x)=x
2,故當(dāng)x∈[-1,1]時(shí),f(x)=x
2,當(dāng)x∈[1,3]時(shí),f(x)=(x-2)
2.
由于函數(shù)g(x)=f(x)-kx-k有4個(gè)零點(diǎn),故函數(shù)y=f(x)的圖象與直線y=kx+k 有4個(gè)交點(diǎn),如圖所示:
把點(diǎn)(3,1)代入y=kx+k,可得k=
,數(shù)形結(jié)合可得實(shí)數(shù)k的取值范圍是 (0,
],
故選C.