Why is the limit of infinitesimal not negative and 0?
Infinitesimal means that although it is too small for us to distinguish, it does exist. Therefore, it should be a number greater than 0. At most, it is too small to be zero. Negative numbers are not only absent, but also insufficient
Is the result of limit 1 / infinitesimal 0?
Because nonzero infinitesimal and infinitesimal are reciprocal, 1 divided by infinitesimal equals 1 times infinity = infinity
Using the property of infinitesimal, the following limits are calculated
(1) Limx squared cos1 / X and then x → 0
(2) Under Lim arctanx / X is x →∞
(1) X ^ 2 is infinitesimal, cos1 / X is bounded function, and the product of infinitesimal and bounded function is infinitesimal, so we directly get Lim x ^ 2cos1 / x = 0
(2) 1 / X is infinitesimal, arctan x is a bounded function, so the limit is 0
This way, there is no more detailed process, because you can get it directly