Question

Calculate the exact value of \[cos \frac{\pi}{3}\]
Tipp: for all \[x \in \mathbb{R}\] valid :
*\[cos(2x)={2cos(x)^2}-1\]
*\[cos(x+\frac{\pi}{2}=-sin(x)\]
*\[cos(x)^2+sin(x)^2=1\]

Answer 1

Okay. Well, remember that \[
\frac \pi 3 = \frac \pi 6 \times 2
\]

Answer 2

Actually, wait a minute.

Answer 3

An equilateral triangle has three sides, which are all \(\pi/3\)

Answer 4

thank you wio, but i need whole solution of the problem, unfortunately i dont have any idea how to do and i must give tomorrow the solution

Answer 5

i would be happy if u can help me