已知直線(xiàn)y=kx+2與雙曲線(xiàn)x^2-y^2=6的左支相交于不同的兩點(diǎn),則k的取值范圍是?
已知直線(xiàn)y=kx+2與雙曲線(xiàn)x^2-y^2=6的左支相交于不同的兩點(diǎn),則k的取值范圍是?
左支哦,
算起來(lái)麻煩那
是x1+x20
且△>0
優(yōu)質(zhì)解答
y=kx+2
x^2-y^2=6
x^2-(kx+2)^2=6
(1-k^2)*x^2-4kx-10=0
△>0,(-4k)^2-4*(1-k^2)*(-10)>0
-24k^2+40>0
-√15/3x1*x2=-10/(1-k^2)>0,k>1,k<-1
x1+x2=4k/(1-k^2)<0,k>1,0>k>-1
1