sin(t)>0 is just another way of saying, sine is positive
and sec(t)<0 is another way of saying, secant is negative
well... if secant is negative, recall [tex]\bf sec(\theta)=\cfrac{1}{cos(\theta)}[/tex] so, then cosine also is going to be negative
now... on what quadrant is sine positive and cosine negative? check your Unit Circle
