## geerky42 Group Title How to find the exact value of $$\cos\left(\dfrac{\pi}{7}\right)$$? one year ago one year ago

pi/7 ?

2. geerky42 Group Title

Yes.

3. geerky42 Group Title

Is it possible to find the exactly value algebraically?

4. starbot Group Title

yes it is possible but I'm not quite sure how

5. Ephilo Group Title

try using the half angle formula

6. geerky42 Group Title

@Ephilo How?