First, let's reduce the angle to something smaller. The sine function is periodic with period 360° (the calculus teacher in me is struggling with using degrees instead of radians).

Yanchun Ding, Guangfeng Shi, Hua Zhang, Guoquan Shi, Dongdong Han, Analysis of critical negative rake angle and friction characteristics in orthogonal cutting of AL1060 and T2, Science Progress (1933- ...