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

Question

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

anonymous · Answer

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

anonymous · Answer

Actually, wait a minute.

anonymous · Answer

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

anonymous · Answer

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anonymous · Answer

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

anonymous · Answer

i would be happy if u can help me

anonymous · Answer

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