已知x平方-5x-2002=0 求X-2分之(X-2)的立方-(X-1)的平方+1
问题描述:
已知x平方-5x-2002=0 求X-2分之(X-2)的立方-(X-1)的平方+1
答
x^2-5x-2002=0
x^2-1997=5(x+1),x+1=x^2/5-1997/5
x^2-2x+1=2003+3x
x^2-4x+4=2006+x
0.5*(x-2)^3=0.5(2006+x)(x-2)
所以,所求方程
f(x)=x^2/5-1997/5-2003-3x-0.5(x^2+2004x-4012)
=0.2x^2-0.5x^2-1005x-(2003+1997/5+2006)
=-0.3(x^2+3350x+44084/3)
=-0.3(2002+5x+3350x+44084/3)
=-5009-1006.5x
x=5/2±√8033
f(x)=-30101±1006.5√8033