The increase in length due to the weight of the wire can be calculated using the formula for elongation under tension:
\( \Delta L = \frac{F L}{A Y} \), where \( F = \rho g L^2 \) is the force due to the weight, and \( Y \) is the Young's modulus.
Match the following:
In the following, \( [x] \) denotes the greatest integer less than or equal to \( x \). 
Choose the correct answer from the options given below:
For x < 0:
f(x) = ex + ax
For x ≥ 0:
f(x) = b(x - 1)2