已知f(x+2)=4x^2+4x+3(x属于R),则函数f(x)的值域为_____
问题描述:
已知f(x+2)=4x^2+4x+3(x属于R),则函数f(x)的值域为_____
答
f(x+2)=4x^2+4x+3 设t=x+2,t属于R,则有x=t-2 f(t)=4(t-2)^2+4(t-2)+3 =4t^2-12t+11 =4(t-3/2)+2 值域为[2,+∞﹚