For visual trig, there's a great interactive unit circle here: http://www.touchmathematics.org/topics/trigonometry http://www.touchmathematics.org/topics/trigo

For visual trig, there's a great interactive unit circle here: http://www.touchmathematics.org/topics/trigonometry http://www.touchmathematics.org/topics/trigonometry Study the way the color-coded lengths vary as theta increases around the unit circle and you'll develop an intuitive sense of sin, cos, tan, etc.