I come to you because I do not like signing up to forums. Here is my problem. It's from the book Calculus: An Intuitive and Physical Approach by Morris Kline.
>An objects slides down an inclined plane OP' starting from rest at O, which is the top of a circle of diameter OP, where P and P' lie in a horizontal line. Show that the point Q reached in the time, t, required to fall straight down from O to P lies on a circle with OP as diameter.
Up until now it was going ok with familiar physics problems done in a way to explain derivatives. Never took trig.