Utiliser les formules d'addition 2

A unit circle in quadrant 1 with 5 points labeled along the circumference. The point at 0 radians is labeled 1, 0. The point at one-sixth pi radians is labeled square root of 3 halves, one-half. The point at one-fourth pi radians is labeled square root of 2 halves, square root of 2 halves. The point at one-third pi radians is labeled one-half, square root of 3 halves. The point at one-half pi radians is labeled 0, 1.