It appears you use Log[y] rather than Cos[y]? Anyway, intersection points can be found with Solve.
Log[y]
Cos[y]
Solve
Solve[Sin[x] == Log[x] && -1 <= x <= 6, x] (* Out[75]= {{x -> Root[{Log[#1] - 2 Tan[#1/2] + Log[#1] Tan[#1/2]^2 &, 2.2191071489137460325958}]}} *)
oh,it was a mechanical error) Thanks, but I need an interval or coordinates of rectangle, where these rectangles overlap. how to find it?
