Fixed-point status is scanned by exact residual rows. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Zero is a true logistic fixed point
The first checked row has output zero and residual zero.
2(0)(1−0)=0
One half is the second exact fixed point
The middle row returns one half, so its residual is also zero.
2⋅21(1−21)=21
A nearby candidate exposes the residual
At three quarters the output is three eighths. The residual table keeps the fixed claim numeric.