# include & ltmath.h & gt
Floating point function (floating point x)
{
Floating f;
f = x * x-2 * x- 1;
Return f;
}
void main()
{
float x 1,x2,x0,fx 1,fx2,fx0
x 1 = 0; x2 = 3;
FX 1 = function (x1);
Fx2 = function (x2);
do
{
x0 =(x 1+x2)/2.0;
Fx0 = function (x0);
if(fx0 * FX 1 & lt; 0)
{
x2 = x0
fx2 = fx0
}
other
{
x 1 = x0;
FX 1 = fx0;
}
}while(fabs(fx0)>= 1e-5);
Printf ("root is %f", x0);
}
Make auxiliary lines as shown in the figure.
Zheng DF parallel AC
Angle BFD = ∠ FDB = 36 = ∠ Ade
Certificate EF=ED=DB?