I know that the function that I search is a sine wave of the form $$A \cdot \sin(x) $$
where my $A$ is unknown. I have samples of the sine wave at discrete points within an interval that's shorter than $\lambda/2$ represented by the red line in the plot.
It must be possible to somehow determine $A=1$ through reconstruction or so from my samples given by the red line. How can i do that?