Applet was designed as an exercise to follow the previous 2 applets (done in consecutive order):
http://tube.geogebra.org/m/1651491
http://tube.geogebra.org/m/1651617
This applet visually guides students to use the 2 new trigonometric identities they've discovered (sine and cosine of a sum) to find the exact value of sin(75) & cos(75).