Hello!
In MATLAB plots, the grid lines fall where the ticks are on the axes.
You can provide custom locations for x and y ticks using code like this:
figure();
plot(1:10);
xticks([1.543 3.543 6.887, 8.5324]);
yticks([1.354 4.654 7.432 9.432]);
grid on;
Then when you turn on the grid, the grid lines will be drawn on the x and y locations you specified.
