I encountered this question:

Is $\cos(x) \geq 1 - \frac{x^2}{2}$ for all $x$ in $R$ ?  

I draw to myself the function graphs but i can't find the right way to answer this type of questions.

[Cosx function graph](https://i.stack.imgur.com/JDc2L.jpg)

[1-x^2/2 function graph](https://i.stack.imgur.com/fzxu9.jpg)