函数f(x)=x^3-(k^2-k+1)x^2+5x-2,g(x)=k^2x^2+kx+1其中k∈(1)设函数p(x)=f(x)+g(x),若p(x)在区间(0,3)上不单调,求k的范围?p'(0)*p'(3)

问题描述:

函数f(x)=x^3-(k^2-k+1)x^2+5x-2,g(x)=k^2x^2+kx+1其中k∈
(1)设函数p(x)=f(x)+g(x),若p(x)在区间(0,3)上不单调,求k的范围?
p'(0)*p'(3)

(1)p(x)=f(x)+g(x)=x^3-(k^2-k+1)x^2+5x-2+k^2x^2+kx+1=x^3+(k-1)x^2+(k+5)x-1
显然p(x)在区间(0,3)上可微,∵p(x)在区间(0,3)上不单调,
∴必有a∈(0,3),使得p'(a)=3a^2+2(k-1)a+(k+5)=0,
解出k=u(a)并注意0