(1)f(-1) = -2f(-1+1)=-2f(0)=-2x0^2=0f(1.5) = -0.5f(1.5-1)=-0.5f(0.5)=-1/8(2)0<=x<=1 f(x) = x^21<=x<拍宽尘=2 f(x) =- (x-1)^2/2 -1<巧春=x<=0 f(x) = -2(x+1)^2-2<袭禅=x<=-1 f(x) = 4(x+2)^2