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问题: 高二数列1

已知定义在R上的函数f(x)满足f(x)+f(x+2)=2x²-4x+2,f(x+1)-f(x-1)=4(x-2),若f(t-1),-1/2,f(t)成等差数列,则t的值为________

解答:

f(x)+f(x+2)=2x²-4x+2 ...(1)
f(x+1)-f(x-1)=4(x-2) ==> f(x+2)-f(x)=4(x-1) ...(2)
(1)-(2) ==> f(x)=x²-4x+3
f(t-1),-1/2,f(t)成等差数列: f(t-1)+f(t)=2*(-1/2)=-1
[(t-1)²-4(t-1)+3]+[t²-4t+3] =-1
==> t =2,3