There is one thing called Taylor Series, which can approximately calculate the value of sin cos and tan function
sin x = x - x^3/3! + x^5/5! - x^7/7! + ... | x is expressed in the form of radian
cos x = 1 - x^2/2! + x^4/4! - x^6/6! + ... | x is expressed in the form of radian
tan x = sinx / cosx