# How do you evaluate #sin((-17pi)/3)#?

##### 1 Answer

How do I know that

Picture an equilateral triangle with sides of length 1. Now cut the triangle into two equal pieces with a line segment running from one vertex to the middle of the opposite side. This will split the triangle into two right-angled triangles with angles 30, 60 and 90 degrees i.e.

Divide this by the length of the hypotenuse (1) to get the sine of the opposite angle (i.e.