已知f(x)={2^x,(x≥4);f(x+1)(x

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/30 17:40:45
已知f(x)={2^x,(x≥4);f(x+1)(x
x){}K4*4m*t4*u.5ѴhjjT$V_`gCY:*ik>01҄oQHӀ@l|v3MMTCih(kc] ^H)TQ\%LF 1H6`΋勡^{g~O=&`mϦ"%8P}@ܩ2/z|`nD Efxںe>0_l*$@{QhRŒF)^lݎ$&

已知f(x)={2^x,(x≥4);f(x+1)(x
已知f(x)={2^x,(x≥4);f(x+1)(x

已知f(x)={2^x,(x≥4);f(x+1)(x
∵ log2(3)∈(1,2)
∴ f(log2(3))
=f(log2(3)+1)
=f(log2(6))
∵ log2(6)∈(2,3)
=f(log2(6)+1)
=f(log2(12))
∵ log2(12)∈(3,4)
=f(log2(12)+1)
=f(log2(24)
∵ log2(24)∈(4,5)
=2^(log2(24))
=24

解log2(3)<log2(16)=4
故f(log2(3))=f(log2(3)+1)=f(log2(3)+log2(2))=f(log2(6))
而log2(6)<log2(16)=4
f(log2(3))=f(log2(6))=f(log2(6)+1)=f(log2(6)+log2(2))=f(log2(12))
而log2(12)<log2(16)=4

全部展开

解log2(3)<log2(16)=4
故f(log2(3))=f(log2(3)+1)=f(log2(3)+log2(2))=f(log2(6))
而log2(6)<log2(16)=4
f(log2(3))=f(log2(6))=f(log2(6)+1)=f(log2(6)+log2(2))=f(log2(12))
而log2(12)<log2(16)=4
故f(log2(3))=f(log2(6))=f(log2(12))=f(log2(12)+1)=f(log2(24))
而log2(24)>log2(16)=4
故f(log2(3))=f(log2(6))=f(log2(12))=f(log2(24))
=2^(log2(24))
=24.

收起