Look at the second formula first. The numerator is constant 10, and the limit of denominator is 1 1.
The limit of the fraction is a definite constant 10/ 1 1, which can be directly substituted to find the limit.
Look at the formula 1 again. If directly replaced, the molecular limit is 0 and the denominator limit is 0.
The limit of the fraction cannot be regarded as a constant, so it cannot be directly substituted.
Because direct substitution essentially replaces 1-cosx with 0,
The higher order infinitesimal is (1/2) x 2.
Therefore, the correct solution of 1 formula is to replace the denominator brackets with 2 (multiplication and division is replaced by infinitesimal).
Then using Roberta's law twice, the limit is 3/4.