函数f(x)=3x-4x3(x∈[0,1])的最大值是( )A. B.-1 C.0 D.1
问题详情:函数f(x)=3x-4x3(x∈[0,1])的最大值是()A. B.-1 C.0 D.1【回答】D【解析】由f′(x)=3-12x2=0得,x=±,∵x∈[0,1],∴x=,∵当x∈[0,],f′(x)>0,当x∈[,1]时,f′(x)<0,∴f(x)在[0,]上单调递增,在[,1]上单调递减,故x=时,f...
问题详情:函数f(x)=3x-4x3(x∈[0,1])的最大值是()A. B.-1 C.0 D.1【回答】D【解析】由f′(x)=3-12x2=0得,x=±,∵x∈[0,1],∴x=,∵当x∈[0,],f′(x)>0,当x∈[,1]时,f′(x)<0,∴f(x)在[0,]上单调递增,在[,1]上单调递减,故x=时,f...