Pendulum broken

Question

How can I fix the pendulum? It keeps going in the wrong direction.

https://code.sololearn.com/WCnwEzPfwrSl/?ref=app

Answer 1

this.x = this.r * cos(this.a-90);
this.y = this.r * sin(this.a-90);

Line19,20

Answer 2

Nice code btw

Answer 3

Thanks!