If the area of triangle \(ABC\) is \(b^2 - (c - a)^2\), then \(\tan B =\)
Show Hint
Whenever expressions like \(1-\cos\theta\) appear in triangle problems, immediately convert them using the half-angle identity:
\[
1-\cos\theta = 2\sin^2\frac{\theta}{2}
\]
This transformation is extremely useful in simplifying area and trigonometric relation questions.