Circles o and bc are tangent to d.
∴od⊥bc
E is eh⊥bc, bc is h,
∫∠ABC = 30
bd=√3
∴od=bdtan30 =√3*(√3/3)= 1
ob=bd/cos30 =√3/(√3/2)=2
And be = ob-OE = ob-od = 2-1=1.
∴eh=( 1/2)be= 1/2
∴s△bed=( 1/2)bd*eh=( 1/2)*√3*( 1/2)=√3/4
∫BF = ob+of = 2+x
cf⊥ab
∴fg=bf*tan30 =(x+2)*(√3/3)=(√3/3)(x+2)
∴s△bfg=( 1/2)bf*fg=( 1/2)(x+2)*(√3/3)(x+2)=(√3/6)(x+2)^2
y=s△bfg-s△bed=(√3/6)(x+2)^2-(√3/4)=(√3/ 12)(2x^2+8x+5)
That is, the functional relationship between y and x is y = (√ 3/ 12) (2x 2+8x+5).
If the area of edgf is 5 times that of △bed, it can be used.
(√3/ 12)(2x^2+8x+5)=5*(√3/4)
X 2+4x-5 = 0。
The solution is x=-5 (truncation) or x= 1.
That is = 1.
∴ef=bf-be=x+2- 1= 1+2- 1=2
And the radius of the circle o is 2*oe=2*od=2* 1=2.
You are fg⊥ab
∴ The positional relationship between the straight line where FG is located and the tangent of circle O to point F.