椭圆x²/a²+y²/b²=1(a>b>0)的离心率为e=1/2
c/a=1/2
c²/a²=1/4
b²/a²=3/4
b=√3/2a
aX²+bx+c=0
ax²+(√3/2)ax+(1/2)a=0
∵a>0
∴x²+(√3/2)x+(1/2)=0
2x²+√3x+1=0
x1²+x2²
韦达定理
=(x1+x2)²-2x1x2
=(-√3/2)²-1
=3/4-1
=-1/4
椭圆x²/a²+y²/b²=1(a>b>0)的离心率为e=1/2
c/a=1/2
c²/a²=1/4
b²/a²=3/4
b=√3/2a
aX²+bx+c=0
ax²+(√3/2)ax+(1/2)a=0
∵a>0
∴x²+(√3/2)x+(1/2)=0
2x²+√3x+1=0
x1²+x2²
韦达定理
=(x1+x2)²-2x1x2
=(-√3/2)²-1
=3/4-1
=-1/4