How much is cos29? Decomposition by micro product, I hope there is a process There are three times how to solve the root 996. I didn't listen to it when I talked about it

How much is cos29? Decomposition by micro product, I hope there is a process There are three times how to solve the root 996. I didn't listen to it when I talked about it

Cosx is first expanded by Taylor formula and then 29 ° is changed into radian
(1000-4)^(1/3)=(1000)^(1/3)+(-4)*1/3
Note that equal is about equal
The formula is derived from Taylor formula
See advanced mathematics textbook for details --