Approximate values of the integral $$I(x)=\int_0^x\cos(t)e^{-t^2 / 10} \mathrm{d}t$$ are given in the following table:
\begin{array}{|c|c|c|c|} \hline x& \pi/2 & \pi & 3\pi/2 & 2\pi \\ \hline I(x)&0.95 &0.44 &0.18&0.22\\ \hline \end{array} then the best approximation of $I(5\pi/4)$ is?
This is a very strange question that I encountered. I tried splitting the bounds of the integral into various intervals but in vain.
Any hint in the right direction is appreciated!
P.S: This post is the same but I wish to seek a simpler answer.
Source: Test of mathematics at the 10+2 level