GATE Civil Engineering (CE) 2023 Shift 1 Solved Paper

The differential equation,
$\frac{\mathit{d}\mathit{u}}{\mathit{d}\mathit{t}}+2\mathit{t}{\mathit{u}}^2=1,$
is solved by employing a backward difference scheme within the finite difference framework. The value of 𝑢 at the (𝑛 − 1) th time-step, for some 𝑛, is 1.75. The corresponding time (t) is 3.14 s. Each time step is 0.01 s long. Then, the value of (un - un -1) _________ is (round off to three decimal places).