Question $3$:

$($Value: $15$ marks$)$

For a square footing of $4m4m,$ determine the average increase in stress at the centre of the area and at a depth of $5m$ due to a uniform loading of $100$kPa. Use any three of the four different procedures $($i$.$e$.,$ point load method, use $m$ and $n$ coefficients, Newmark's chart, and trapezoidal rule$)$ and compare the results.

Also explain trapezoidal rule