Bonsoir,
On a :
- CM = f(x)
- AOC rectangle en A
- OM = OA
- x = 30°
- AC = 3cm
Donc avec la trigonométrie on peut calculer OC et OA.
cos(x) = AC/OC
OC = AC/cos(x)
OC = 3/cos(30)
tan(x) = OA/AC
OA = tan(x)×AC
OA = tan(30)×3
MC = OC - OM or OM = OA = tan(30)×3
donc on a:
MC = 3/cos(30) - 3tan(30)
MC ≈ 1,732cm
f(30) = 1,732cm
