椭圆x^2/a^2+y^2/b^2=1(a>b>0)的俩顶点为A(a,0)B(0,b),且左焦点为F,△FAB是以角B为直角的直角三角形,则椭圆的离心率e为.

椭圆x^2/a^2+y^2/b^2=1(a>b>0)的俩顶点为A(a,0)B(0,b),且左焦点为F,△FAB是以角B为直角的直角三角形,则椭圆的离心率e为.
椭圆x^2/a^2+y^2/b^2=1(a>b>0)的俩顶点为A(a,0)B(0,b),且左焦点为F,△FAB是以角B为直角的直角三角形,则椭圆的离心率e为.

椭圆x^2/a^2+y^2/b^2=1(a>b>0)的俩顶点为A(a,0)B(0,b),且左焦点为F,△FAB是以角B为直角的直角三角形,则椭圆的离心率e为.
AB^2=a^2+b^2
BF^2=b^2+c^2
AF^2=(a+c)^2
由于ABF为直角三角形 所以 AF^2=BF^2+AB^2
即a^2+2ac+c^2=a^2+2b^2+c^2
又b^2=a^2-c^ 将它带入上式
得c^2+ac-a^2=0
两边同除以a^2,e=c/a
所以e^2+e-1=0
后面的方程求解应该会的吧,打出来有点麻烦就不打了

Most of the traditional e-commerce business is not too successful. With courage and spirit of enterprises reached, but then go like "rookie into the jungle,cheap nike air max 90 shoes," can not find t...

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