#1**+3 **

If I understand this.....you are looking for " - - " ????

Looking at the right side

(1/2) [ sin pi/2 - sin pi/6 ] =

(1/2) [ 1 - 1/2] =

(1/2) (1/2) = 1/4

So

" - - " pi/3 * sin pi/6 = 1/4

" - - " pi/3 * (1/2) = 1/4 multiply both sides by 2

" - - " (pi/3) = 1/2

The " - - " is "cos "

CPhill Apr 26, 2019