设X1X2是方程2x²+4x-3=0的两根.求(x1+2)*(x2+2) x2/x1+x1/x2
问题描述:
设X1X2是方程2x²+4x-3=0的两根.
求(x1+2)*(x2+2) x2/x1+x1/x2
答
设X1X2是方程2x²+4x-3=0的两根.满足 x1+x2 = -2 x1x2 = -3/2 求(x1+2)*(x2+2) = x1x1 + 2 (x1+x2) +4= -3/2 - 4 +4= -2分之3x2/x1+x1/x2= (x1²+x2²) /x1x2=[ (x1+x2) ² - 2x1x2 ] /x1x2= ( ...