Try this solution (if it is possible, check it in other sources):
1.
[tex] \lim_{x \to 0} \frac{sin2x}{x} =2 \ (x \to 0+0; \ x \to 0-0).[/tex]
2. using the item 1, the best range is x=-0.03;-0.02;-0.01;0.01;0.02;0.03, it is including the positive and negative values of x.
answer: -0.03; -0.02; -0.01 etc.
