高一数学4
已知F(X)=AXX-C
且-4<=F(1)<=-1,-1<=F(2)<=5
求F(3)的取值范围
参考答案:F(1)=A-C
-4<=A-C<=-1
F(2)=4A-C
-1<=4A-C<=5
F(3)=9A-C=m(A-C)+n(4A-C)
{m+4n=9
-m-n=-1 m=-5/3 n=8/3
F(3)=-5/3F(1)+8/3F(2)
-1<=F(3)<=44/3
已知F(X)=AXX-C
且-4<=F(1)<=-1,-1<=F(2)<=5
求F(3)的取值范围
参考答案:F(1)=A-C
-4<=A-C<=-1
F(2)=4A-C
-1<=4A-C<=5
F(3)=9A-C=m(A-C)+n(4A-C)
{m+4n=9
-m-n=-1 m=-5/3 n=8/3
F(3)=-5/3F(1)+8/3F(2)
-1<=F(3)<=44/3