(1)
f(x) 為奇函數(shù),則有 f(-x) = - f(x)
令t < 0
則有 -t > 0
那么
-f(t) = f(-t) = (-t)^2 -2(-t) = t^2 + 2t
所以 f(t) = - t^2 - 2t
綜上
f(x) = x^2 -2x 當(dāng)x >=0
= -x^2 -2t 當(dāng)x0
那么
f(t) = f(-t) = (-t)^2 -2(-t) = t^2 + 2t
所以 f(t) = -t^2 + 2t
綜上
f(x) = x^2 -2x 當(dāng)x >=0
= t^2 + 2t 當(dāng)x