The Trigonometery functions in other presentation

[DaniV]

Can I present the trigonometry functions (such as SinX, CosX, TanX, CotX) by using only- Log, Lan, multiplication, division, addition, subtraction, exponantion, nth root operations?

 

[jedishrfu]

Welcome to PF!

The trig functions can be represented by infinite series where addition, multiplication and exponentiation are used. These are used to actually compute the values of a trig function numerically:

https://en.wikibooks.org/wiki/Trigonometry/Power_Series_for_Cosine_and_Sine

and others are presented in this article:

https://en.wikipedia.org/wiki/Trigonometric_functions

 

[mathman]

Using complex functions, you can represent $sin(x)=\frac{e^{ix}-e^{-ix}}{2i}\ and\ cos(x)=\frac{e^{ix}+e^{-ix}}{2}$.